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I thought it might be good to start a thread about what things to keep an eye on in terms of vehicle maintenance in order to prevent problems.
I know that many of the contributors here are seasoned mechanics or Nissan Owners but for those of us who are new to the game there is just so much to learn.....
I have recently purchase a 1998 GU 4.2TD with 350 K on the clock. This is my first 4wd and so I am learning as I go. What I am keen to learn is what things I need to keep my eyes on in order to prevent major problems.
I would greatly appreciate those of you with experience if you could contribute to this thread and just list some things to check or look out for.
I know the obvious things - clean oil, keep her cool, clean air but there are a million other things which can go wrong if left un-checked. Also if anyone has any links or resources which might help me to get my head around the vehicle and keep her in good nick.
There is a lot of information to put in here so this post/thread will keep growing over time, I'll add photos as I can.
This is by no means a complete or definitive guide, my aim is to give people some basic things to look for as well as some general information about Nissan Patrols. This information primarily applies to GQ/GU (Y60/Y61) Patrols as they are the most common models and the only models I have direct experience with. If you have any questions however silly they may seem, please feel free to ask. PM me you phone number if you want to talk to me directly, I don't mind helping people.
Don't be put off by the amount of text, I'm trying to help people understand their cars, not just check this check that.
ENGINE
OIL LEAKS; Patrol engines in general are not prone to leaking lots of oil, but it does still happen. Finding the exact source of an oil leak is not always easy. If you do a lot of mud driving then don't be surprised if your front crank seal starts leaking. This is one of the easier leaks to diagnose, oil will leak down the front of the sump and in most cases be thrown out from the crank pulley.
Oil leaking around the rear of the sump is usually coming from the rear main (rear crank seal), check carefully in both cases to make sure it's not coming from higher up.
Oil pressure sender units have been known to fail and leak oil.
If an oil leak or combination of leaks is bad enough the whole engine could end up covered in oil making it nearly impossible to find the source of the leaks. The best thing to do in those cases is to degrease the whole engine, then go for a drive and recheck for leaks.
HEAD GASKETS; The head gasket is the gasket fitted between the cylinder head and the engine block. Head gasket failure can show in a number of ways. External oil or coolant leaks will show below the cylinder head, coolant leaks will generally show as a white or pale green stain down the side of the engine block. Internal leaks are more difficult to diagnose, but as this thread is concentrating on preventative maintenance I won't go into the diagnosis here.
The one suggestion I will make is to always look at the underside of your oil filler cap every time you take the cap off. If you see a milky brown paste under the cap, it's usually a good indication that coolant is leaking into the lubrication system, usually from a blown head gasket. Depending on the severity of the leak you may also find the same milky paste under the radiator cap and/or on the dip stick.
WELCH/FREEZE PLUGS; Welch plugs are the pressed steel plugs pressed into the side and sometimes rear of the engine block. Because they are made of pressed steel they are susceptible to corrosion if correct coolant levels are not maintained. Check each of the welch plugs carefully for signs of rust or coolant stains.
OIL COOLER; TD42 diesel engines are fitted with an engine oil cooler bolted to the engine block on the intake side. The oil cooler forms part of the engine cooling system and is therefore also subject to corrosion if correct coolant levels are not maintained. Leaks may be external as a coolant stain down the intake side of the block, or internal and mix engine oil with coolant. Oil cooler failure will present similar symptoms to a head gasket. Look for coolant stain down the intake side of the engine block, milky brown paste under the oil filler cap and/or radiator cap, and on the dip stick.
TB series petrol engines have a steel plate on the side of the engine block in the same position as the TD42's have the oil cooler. Look for rusting of the steel plate or coolant stains around it.
GENERAL INFORMATION;
TD42 oil filter changes;
GQ TD42 NA 2/88 to '97 uses Ryco Z115 (x2)
GU TD42NA 5/98 to '03 uses Ryco Z503 (x2)
GU TD42T 5/99 to '05 uses Ryco Z416 (x1) and Ryco Z503 (x1)
Please note, I use Ryco part numbers as an example only, use what ever brand oil filter you are comfortable with.
COOLING SYSTEM
RADIATOR; Check for blockages in the external fins. Remove the top radiator mounts and carefully push the radiator back. Look down between the radiator and A/C condensor as all sorts of rubbish can collect between the two and restrict air flow. It can be very hard to see with the radiator in the vehicle but also try to look for mud caked up in the fins. My brother cooked the engine in his Navara after going through a mud hole. The wet mud dries quickly when it hit the hot radiator and seriously reduces the cooling capacity of the radiator. Guess who got to replace that engine?
Another thing that's difficult to check for but worth doing, is checking the condition of the fins themselves. Lightly rub your fingers over the surface of the fins, if the fins start to disintegrate and fall out then it's time for a new radiator.
RADIATOR CAP; Without a proper pressure tester it's not possible to check the cap properly, but you can check the main rubber seal. Look for soft compliant rubber with no cracking or swelling. Given the low cost of radiator caps, if you're in any doubt about it's condition just replace it.
HOSES; Check hoses for swelling where they slip over the water pump, thermostat etc. Swelling at these points indicates corrosion on the aluminum housings. If the hose is swollen, replace it. I recommend replacing the corroded item as well, while you may get away with cleaning the corrosion off and fitting a new hose for a while, the corrosion almost always returns.
Squeeze the hoses, if they feel solid and make a cracking sound as you squeeze them then there is a calcified build up inside them and they need to be replaced.
Also, a hose may look and feel OK, but that does not always mean they are OK-I've been caught. The hose seemed fine when I serviced the car, but a few days later split open down the length of the hose. On closer inspection when you pushed your fingers into the hose from the outside, you could see cracks opening up inside the hose. If your in any doubt, or are planning a big trip and your hoses are more than 12 months old, replace them (all of them) and keep the old hoses for spares. Check the tension of the hose clamps (obviously this does not apply to the spring type hose clamps) a couple of times a year. When you replace hoses it is very important to recheck clamp tension a few days after you fitted the hoses, as the hoses will settle a bit after they've been heated and cooled a few times. [photo to be added later]
BELTS; Use a torch and have a very close look at your belts. Look for cracks appearing on the "V" side of the belt, pieces missing or frayed pieces. On a multi V belt the cracks may be very small. If your in any doubt or are planning a long trip, replace the belts, all of them. You might think that it does not matter if the A/C belt breaks, you can live without A/C for a while, but often when a belt breaks it will take out or damage the other more important belts. Broken belts can also lodge between the back of the crank pulley and the front of the engine, damaging the front crank seal. While the belts are off, give each idler pulley a spin listening for anything other than smooth quiet movement. Check belt tension about every month, just a quick push with your finger on the long span between pulleys. On a span of about 30cm you should have about 1cm movement. For engines with automatic tensioners check the tensioner for signs of wear.[photo to be added later]
WATER PUMP; Check the water pump shaft for vertical movement, for vehicles with an engine driven fan simply grab both sides of the fan and try to lift it up a few times, there should be no movement.
Use a torch and have a look at the water pump from underneath, look for a coolant stain or drips of coolant on the water pump housing. If you find shaft movement or leaks, replace the pump.
FAN; For vehicles with engine driven fans, look for cracking in the plastic around the centre of the fan, this is very common on Patrols. If it's cracked, replace it.
FAN HUB; For vehicles with engine driven fans, look for oil leaks from the fan hub. With the engine cold and stationary try to spin the fan by hand, it should stop within about a 1/4 to 1/3 of a turn. Start the engine, when you first start it and bring the revs up to about 1500rpm you should hear the fan roar for a while then go quiet. Keep the engine running and the revs at that point or there abouts. As the engine reaches full operating temperature you should hear the fan cycling, it will start to roar for 30 seconds to a minute then go quiet again. The on time of the fan will be extended on a hot day after a drive.
COOLANT; Without specialised tools the only way to judge coolant condition is by appearence. Rusty brown is bad, green,red, or blue is usually OK. This is only a guide, coolant should be replaced at or before manufactures recommendations and to specified concentration. Do not mix different types of coolant, if you are not sure what was in there previously, drain it, fill it with water (or coolant flush solution) run it until the engine is hot, and drain it again to flush out the old coolant. Some Nissan motors are fitted with an engine block coolant drain plug, where fitted they are usually at the back of the engine on the exhaust side [photo to be added later].
BLEEDING COOLING SYSTEMS; If you drain any coolant from your engine it is important to bleed all of the air out afterwards. Any air pockets that remain in the engine (which will be in the cylinder head) can potentially cause cracking of the cylinder head.
Bleed it by removing the radiator cap and letting the engine idle until the thermostat opens (when the coolant starts moving and the air the fan is pulling through the radiator suddenly gets warmer). Recheck coolant level after a few days.
Fuel injected 4.2 petrol (TB42E) have coolant bleed screws on top of the inlet manifold, be VERY careful as they have a habit of seizing into the aluminum and breaking off when you try to remove them. Because of this I now only bleed them as described above.
GENERAL INFORMATION;
STRAY CURRENT.
Tony
Last edited by YNOT; 13th December 2010 at 10:20 PM.
DIFFERENTIALS; First thing to check is oil leaks (note: oil leaks may also be caused by blocked breathers, see third paragraph). Oil leaking from the front of the diff where the tail shaft attaches indicates a leaking pinion shaft seal. Oil leaking down the brake backing plates indicates a leaking inner axle seal. Patrol (coil spring models) wheel bearings are lubricated by grease, there is a seal (inner axle oil seal) inside the ends of the diff housing [photo to be added] that keeps the diff oil separate from the wheel bearings, when this seal leaks diff oil washes through the wheel bearings diluting the grease. So don't just replace the seal, clean and repack the wheel bearings. Don't try to remove the rear wheel bearings to repack the grease as the job requires specialized tools. Front wheel bearings should be cleaned and repacked with grease about every 40,000km, more frequently if you like deep water crossings. Front wheel bearing adjustment should be checked every service. Check by jacking under the front diff until the tyre is about an inch off the ground and supporting the diff on axle stands. Hold the tyre top and bottom, try to push the top of the tyre in while pulling the bottom of the tyre out then alternate back and forth, there should be very little movement.
Nissan Patrol diff housings (H233B diffs) have been known to crack. This usually occurs in the area on either side of the pumpkin [photo to be added], I have had a report of one diff the cracked along the top of the housing as well. The cracks normally appear first as an oil leak from these areas. In most cases the housings can be repaired by a qualified welder, though it probably pays to fit diff strengthening brackets (available from Superior engineering) if your housing needs to be repaired.
Check your diff breathers and breather hoses[photo to be added]. As the diffs warm up the air inside expands, breathers are fitted to allow this to vent. If the breathers become blocked the air will push out past the axle or pinion seals taking oil with it. Also be aware that when the diffs are hot and you suddenly plunge your vehicle into a deep river crossing, the diff can cool quickly and drawer air back in through the breathers. If the breathers are blocked or the hoses cracked or not fitted, water will be drawn into the diff. Water is not a lubricant so breathers play an important role. If you plan to do river crossings I suggest you invest in an extended diff breather kit.
Diff oil should be replaced about every 40,00 km, more frequently if you like deep water crossings. Always remove the fill plug before removing the drain plug. You don't want to find out the fill plug is jammed in AFTER you've drained the oil. If when you remove the fill plug you notice oil draining out the fill hole, either the oil has been over filled or there is water in the diff. When you do drain the oil, inspect the swarf magnet on the drain plug. It is normal to find fine iron filings on the magnet, but if you find chunks of metal you need to be asking questions. Look at the oil as it drains out, looking for water (water is a lot thinner than diff oil) or milkiness indicating water has mixed with the oil. Clean the fill and drain plugs before refitting, and it doesn't hurt to put a bit of sealant on the threads. When refilling diff oil, fill to the bottom of the fill plug with the car parked on a flat level surface.
Front 5.4 litres, rear (LSD)2.1 litres (factory locker)3.0 litres,** H260 4.7 litres.
**H260 rear diff fitted to most manual GU 3l, 4.5l and 4.8l Patrols.
GENERAL INFORMATION;
GQ/GU (Y60/Y61) H233b differentials are different, GU diffs are approximately 40mm longer and GU front CV joints are are lot stronger. Rear diffs are a straight bolt in swap. Front diffs also bolt straight in but require a longer drag link. Refer to general information in the steering section below for more information on drag links.
H260 rear diffs bolt straight in but MAY require a different tail shaft. I've never swapped a H233b for a H260 so I don't know for sure. H260 diffs are stronger than H233b but getting lockers is more expensive.
GEARBOX; Not so much to look out for here, both of the manual gearboxes fitted to GQ/GU (Y60 and Y61) Patrols are very robust and reliable. RB30 and RD28 engined Patrols got a smaller (alloy case) box than the rest.
On both gearboxes check the rubber boot around the base of the gear lever directly on top of the box. This boot has a habit of splitting or perishing, allowing contaminants to enter the internals of the box. Unless you have a body lift this rubber boot is going to take a bit of work to check - nothing difficult. My advice, if you're going to the trouble of checking it, go down to Nissan before hand and get a new boot. They're cheap and readily available, and replacing it only takes a few minutes more than checking it. If you have a gear oil smell coming into the cabin this is the first place I would look.
To check or replace remove both front seats, both gear knobs and center console. Remove the front carpet. You will now see a plate bolted to the floor surrounding the gear levers. Remove this plate and you will be able to see the boot at the base of the main gear lever.
Listen for gearbox noise, it's usually the first indication of gearbox problems. Some noises can be heard while driving, others you can hear while stationary. There's too many different noises to go into here so if you have a gearbox noise, make a note of when and where it happens and start a new thread. We can help you diagnose it from there.
Early GU Patrols (excluding RD28) had a weakness in the fifth gear splines. Nissan released some update parts to rectify the fault but there is no external way to determine if you have the update parts.
The 5 photos below show 5th gear parts.
Gearbox oil should be replaced about every 40,00 km, more frequently if you like deep water crossings or do a lot of 4WDing. Always remove the fill plug before removing the drain plug. You don't want to find out the fill plug is jammed in AFTER you've drained the oil. If when you remove the fill plug you notice oil draining out the fill hole, either the oil has been over filled or there is water in the diff. When you do drain the oil, inspect the swarf magnet on the drain plug. It is normal to find fine iron filings on the magnet, but if you find chunks of metal you need to be asking questions. Look at the oil as it drains out, looking for water (water is a lot thinner than gearbox oil) or milkiness indicating water has mixed with the oil. Clean the fill and drain plugs before refitting, and it doesn't hurt to put a bit of sealant on the threads. When refilling gearbox oil, fill to the bottom of the fill plug with the car parked on a flat level surface.
Check gearbox breathers as described in the third paragraph of diff section.
GEARBOX OIL; 80w90 gear oil
3.9 litres for big G/box, 3.6 litres for RB30 and RD28.
TRANSFER CASE; Not much goes wrong with Patrol transfer cases, they can take a huge amount of punishment (and horsepower) and rarely fail. The transfer case is the same across GQ/GU models regardless of engine or gearbox. Low range ratio is 2.02:1. Not a particularly low reduction with low first being the only gear lower than first high, but aftermarket reduction gears are readily available in a variety of ratio's.
Except for GU 4.8l, GQ/GU Patrols are fitted with a transfer case mounted drum handbrake with very strong holding ability. The handbrake (on the rear of the TF case) can be adjusted easily by removing a rubber bung from the drum, moving the drum so the hole is in the 6 o'clock position, and using a screw driver through the hole to move the adjuster.
Transfer case oil should be replaced about every 40,00 km, more frequently if you like deep water crossings or do a lot of 4WDing. Always remove the fill plug before removing the drain plug. You don't want to find out the fill plug is jammed in AFTER you've drained the oil. If when you remove the fill plug you notice oil draining out the fill hole, either the oil has been over filled or there is water in the diff. When you do drain the oil, inspect the swarf magnet on the drain plug. It is normal to find fine iron filings on the magnet, but if you find chunks of metal you need to be asking questions. Look at the oil as it drains out, looking for water (water is a lot thinner than transfer case oil) or milkiness indicating water has mixed with the oil. Clean the fill and drain plugs before refitting, and it doesn't hurt to put a bit of sealant on the threads. When refilling transfer case oil, fill to the bottom of the fill plug with the car parked on a flat level surface.
Check transfer case breathers as described in the third paragraph of diff section.
TRANSFER CASE OIL; 80w90 gear oil 2.2 litres
CLUTCH; Not much can be checked here and unfortunately Patrol clutches give very little warning they are about to fail. I've heard one story from a club member who after spending all week end driving around a 4WD park, packed up and left all without a problem. They pulled up to pay a toll, and had no drive when they went to pull out. It's not the first time I've heard of that happening.
AUTO TRANS; Again not much can be checked. Oil level obviously, and condition. Look at the color of oil on the dip stick, it should be a deep red color. If it's very dark going on black, and smells burnt, the transmission is not going to last much longer.
While driving feel for smooth consistent gear shifts. There shouldn't be any slipping or flaring (engine revs rising during up shifts). Also feel for torque converter lock up shudder. At speeds over about 80km/h a lock up clutch in the torque converter engages to eliminate all converter slip, this feels a bit like it's engaging 5th gear and the tacho will drop about 400rpm. Shuddering during this engagement is common on auto Patrols and usually requires a new torque converter. You can keep driving (the shuddering is only during the engagement, once it's engaged fully it drives normally) with this condition, but the risk is that lock up clutch material from the worn linings can be circulated through the rest of the transmission by the fluid and do more expensive damage.
If you do any towing or 4WDing then fitting a BIG transmission cooler is mandatory. The biggest killer of automatic gearboxes is overheated transmission fluid. Fitting a sump guard under the transmission pan is also a good idea.
AUTOMATIC TRANSMISSION FLUID; Nissan Matic D 8.5 litres
**BRAKES AND STEERING ARE CRITICAL SAFETY SYSTEMS DO NOT ATTEMPT TO SERVICE THESE SYSTEMS UNLESS YOU KNOW WHAT YOU ARE DOING**
BRAKES; The vast majority of GQ/GU Patrols (and Mavericks) were fitted with 4 wheel disc brakes, only a few early base models had drum rear.
BRAKE PADS; Check brake pads every service, the minimum brake pad thickness you want to see is 2.5mm anywhere on any of the pads, they don't always wear evenly so check carefully. Some brake pads are fitted with a small metal tag that is designed to come in contact with the disc rotar as the pad wears down to minimum thickness. When the tag touches the disc it makes a very irritating squeal. So if you hear a loud squeal start emminating from your brakes, DON'T IGNORE IT, it may be your brake pads warning you they need to be replaced soon. My personal preference for brake pads is Bendix 4WD pads.
Uneven brake pad wear is often caused by sticking brake calliper slides. These slides allow the calliper to 'float' over the disc and self centre. When the slides stick the calliper can not move freely and uneven pad wear is the result. You will need to remove the brake calliper to check the slides properly.
BRAKE DISC ROTARS; Brake disc rotars are also subject to wear and have minimum thickness specifications that must be adhered to. Specifications vary by model and I'll try to track down the specs. Accurately checking the thickness requires special calipers, but as a general rule if the rotars have a reasonable size lip around the outside and generally look worn, it's probably time to either get them professionally inspected or just replace them. If the rotars are above minimum thickness it's a good idea to get them machined when ever you replace the pads.
BRAKE FLUID; Brake fluid is a hygroscopic hydraulic fluid. Hygroscopic means it absorbs water, which is important in an automotive braking system. The downside is that once the moisture content of brake fluid reaches 4% there is a serious risk of the water that has been absorbed by the fluid turning to steam if the brakes get hot enough (as they do on long descents). Steam is compressible and the result is the brake pedal going to the floor and a loss of brakes. This is why brake fluid MUST BE REPLACED EVERY 2 YEARS REGARDLESS OF KILOMETERS.
Brake fluid is generally blue or green in color and should be clear not cloudy in the reservoir.
Replacing brake fluid is not difficult but needs to be done properly due to the safety aspect. It's not just the fluid in the reservoir that needs to be replaced, the clean fluid also needs to be pumped right through the brake system.
MASTER CYLINDER; Check the brake master cylinder (under the reservoir) for any signs of fluid leaks. Ensure the cap is properly fitted to keep moisture out.
BRAKE HOSES; Brake hoses need to be checked every service for cracking and any other sign of deterioration. For vehicles with anything over a 2 inch lift the standard hoses will be too short and longer hoses will need to be fitted. Any replacement brake lines must be ADR (Australian Design Rule) approved.
STEERING;
Checking for wear in steering components;
To check for wear in steering components you will need two people.
First person to operate the steering, second person underneath the car looking for excessive movement.With the engine off, person one needs to rock the steering wheel (from the straight ahead position) from left to right at the rate of about once per second. The steering doesn't need to be moved far, if they put one hand at the top of the wheel and move it from about the 11 o'clock position to 1 o'clock position is usually enough.
Person two needs to carefully inspect each steering joint, watching, feeling and listening for wear at each joint. For example, the drag link rod end where it attaches to the pitman arm on the steering box. As the pitman arm moves back an forth, the drag link should move with it, there should not be any movement in the joint on the end of the drag link or any of the other joints.
DRAG LINK; The joints on the end of the standard drag link (the steering arm in front of the front diff) are part of the link and can not be adjusted or replaced. If you find any wear in the joints it will need to be replaced. I recommend replacing the standard fixed link with an aftermarket heavy duty adjustable drag link. With the drag link sitting out in front of the diff it is exposed and easily damaged, aftermarket drag links are a lot stronger. Fitting an adjustable link will allow you to properly centre the steering if required. (moving the steering wheel on its splines does not centre the steering).
For those who like their 4WDing a little more hardcore, pay the extra and get a competition spec drag link with female threaded rod ends.
TIE ROD; The tie rod (the steering arm behind the front diff linking the left and right steering hubs together) is adjustable and has replaceable rod ends. The tie rod is adjusted to set toe in when you get a wheel alignment. For hard core off roader's the tie rod can be replaced with a heavy duty part.
KING PIN/SWIVEL HUB BEARINGS; King pin or swivel hub bearings need to be checked for wear and pitting. There are two ways to do this. First way is to jack the front wheels off the ground (support on axle stands) and remove the wheels. Next remove the tie rod, and the diff end of the drag link. Swivel both the swivel hubs slowly, the should move smoothly and without binding. If they fall into a definite centre position then the bearings are pitted and need to be replaced.
The other way to check them is to remove the bearings and inspect the visually. Be aware before you remove the king pin/swivel hub bearings that there is usually a shim or two between the square bearing cap and the swivel hub housing, these shims need to be refitted in the same position as they set the bearing pre-load.
If you've been driving through deep water it is a good idea to periodically remove one bolt from each of the bottom swivel hub bearings to allow any trapped water out. If you do find water has been trapped it would also be a good idea to repack your front wheel bearings and possibly CV joints.
Do this check at each service as a minimum.
FLEX JOINT; Check the flex joint in the steering shaft, just outside the fire wall. The flex joint has a rubber disc in it that is subject to wear. Look for elongation of the holes, cracking and perishing of the rubber.
The flex joint is designed in such a way that if the rubber disc does fail, the steel components of the joint can contact each other so you can still steer the car, though the steering will have a lot of free play.
STEERING BOX AND PUMP; Check for wear in the steering box, this needs to be done with the steering in the straight ahead position. You may need the person operating the steering to slow right down to do this. Watch the pitman arm (the output side of the steering box that the drag link attaches to) VERY carefully as the steering is getting rocked. If you compare the movement of the steering shaft going into the steering box to the movement of the pitman arm you should see a very small amount of free play where the pitman arm does not move. It really takes a trained eye to know what is normal but have a look anyway. If you think the movement is excessive, get a professional to have a look at it.
Also check the power steering box, pump and hoses for oil leaks. If you do find oil leaks or wear in the box or pump, best leave it to the pro's to overhaul them. A lot of steering and brake specialists do exchange components, so if you're handy on the tools you can save on labour by removing and refitting the components yourself. If you get an exchange steering box, ask them to swap the pitman arm over for you - they're a bugger of a thing to get off!
STEERING DAMPER; Check the steering damper for impact damage, oil leaks and bush wear.
POWER STEER FLUID; Dexron II 1 litre
GENERAL INFORMATION;
GQ and GU (Y60/Y61) steering boxes are different, the GU box is stronger with a bigger output shaft. You can fit a GU steering box to a GQ, BUT, not with a standard drag link. You will need an adjustable drag link as the pitman arm rod end needs to be inverted to fit the GU pitman arm. GQ/GU drag links are different lengths (GU is longer) so they are not interchangeable unless you fit a GU front diff, see general information in the differential section above.
Steering dampers may look like shock absorbers, but there is a difference. Shock absorbers have different valving and therefore damping rates on their compression and rebound strokes, steering dampers have the same valving/damping in both directions.
Tony
Last edited by YNOT; 9th December 2010 at 10:03 PM.
RADIUS ARMS; The front radius arms are the arms which extend from the chassis forward to the front diff. Look for cracking or perishing of the bushes. To do this you will need a good torch and have a very close look, cracks can be difficult to see. Levering the arms side ways with a suitable lever bar can make it easier to see by opening up the cracks.
TRAILING ARMS; Rear trailing arms extend from the chassis to the rear diff. There are 2 upper and 2 lower arms. Check the bushes as described above, also check the lower rear control arms for bends.
The lower control arms are made from thin tubing and are venerable to impact damage. If the lower control arms get damaged they can fold easily allowing the diff to rotate. In some cases this can just be inconvenient with the tyres rubbing on the front of the wheel arches, but if you're giving it hell when you bend an arm, it can lead to the tail shaft being twisted, diff pinion being torn off and shock absorbers being destroyed. Aftermarket heavy duty lower arms are readily available for exactly this reason.
PANHARD RODS; Panhard rods are the arms fitted between the chassis on the RH side to the diffs on the LH side. They are fitted front and rear to control lateral movement of the diffs.
Check the bushes for cracks and perishing as described above.
Some Nissan parts interpreters will try to tell you the bushes are not available separately and that you need to buy a complete panhard rod - not true. Companies like Superior engineering and Nizzbits can get you genuine Nissan bushes separately.
I've seen and felt what happens when front panhard rod bushes fail, and it's very dangerous. Usually after going over a sharp bump at 60+km/h, the front diff can develop a violent lateral oscillation or shake that can rip the steering wheel clean out of your hands - not something you want to have happen at 100km/h trust me!
Check your panhard bushes carefully and NEVER fit cheap poly bushes.
SHOCK ABSORBERS; Shock absorbers are designed to control or dampen the action of the springs.
The first thing to look for with shock absorbers is visual signs of wear and oil leaks. Check all the bushes for cracking and perishing, check the body of the shocks for impact damage and signs of leaking oil.
It's not possible to check shock absorber performance properly without proper testing equipment, but you can get an idea by doing a bounce test. Leaning on one corner of the car at a time, start bouncing the car as far as you can. When you've got a good bounce happening let go and watch. If you let go on the down (compression) stroke, the suspension should rise, fall and settle. if it continues to bounce past that it's time to see a suspension specialist.
SWAY BARS; Sway bars are spring steel bars fitted across the car, connected in two points in from the ends to the diff housings, and at the ends to the chassis via link pins. Their purpose is to reduce body roll or sway.
Check the bushes and/or ball joints on either end of the link pins. As with any bush or ball joint they are subject to wear.
GENERAL INFORMATION;
Rubber v poly bushes
When it comes to four wheel drives, if you want to get maximum suspension travel you need bushes that can flex and allow the suspension to move freely. Good quality poly bushes (don't bother with cheap ploy bushes, they're a waste of time and money) are durable and do a great job of locating various suspension components, but in most cases they are too stiff to allow the suspension to move freely. This is especially true for radius arm bushes in Patrol front ends.
Genuine Nissan rubber bushes for coil sprung Patrols are relatively cheap, durable and readily available.
Tony
Last edited by YNOT; 9th December 2010 at 10:39 PM.
The Following 10 Users Say Thank You to YNOT For This Useful Post:
ahimz (5th December 2013), Airstrike (22nd February 2012), choppie (4th February 2012), cossy (27th January 2011), dom14 (19th August 2013), DX grunt (12th November 2010), Grumpy (3rd May 2012), nassin (13th February 2011), Robert 99 gu (18th July 2014), Sherro (13th March 2014)
Tony this is FANTASTIC!!!!! Thank you mate, and thanks for starting so quickly. I am going to make a start on some of the things you suggested straight away. I have been trying to get my head around things using the workshop manuals I have but there is often alot of information they assume you know and they don't always explain themselves very well.....I think this thread will be very helpful to people like me who are just starting out with their 4wd and have a limited mechanical background. At the end of the day doing your own maintenance saves you in the hip pocket, even just changing your own oils, coolant, belts and fluids makes a difference not to mention that you end up understanding your vehicle so much better than if you just take it in to the local mechanic periodically. Again thanks a heap! Even my wife was impressed......and that is something!!
Just thinking about doing the belts and hoses on the patrol as Tony has suggested. I am wondering if anyone knows where to get a value for money kit? I have looked on Ebay and a kit for both belts and radiator hoses is around the $149 mark, I also looked at a few others online....is this good value?