GQ Swivel hubs gets very hot

hello all,

I have a 94 Patrol, TD42, running on 285/75r16 tyres. Noticed when I was trying disengage my hubs after a tackling a track, it was almost impossible to try to hold and turn to disengage the hubs.

To try to resolve the problem I recently had my front hubs and bearings completely serviced. In addition new front rotors and all four corners have been serviced at the same time. It didn't help. :(

If I was to go for a drive out to the sticks, straight road, no traffic etc the hubs get warm which I believe is within normal operating temperatures. However, if I were using my breaks eg. general start/stop, up and down tracks or even hilly windy roads the hubs get too hot to touch. Today I took the Patrol for a short drive to a local hilly area and then went to a mates' shop to have the temperature read. It was 79.9 degrees Celsius on both front hubs.

Does anyone have any idea what would cause this and how to resolve this? I also read somewhere running bigger tyres may be a possible cause. is this normal for a GQ? What should the standard operating temperature be?

Have you stripped and serviced the actual Hubs. are they Auto hubs of manual hubs? Sounds like manual hubs. they can be stripped and re packed. what grease is in them will make a bit of a difference too.

Check your wheel bearing tension too.

Mine get warm to hot but not that hot you can't touch them .

I think you mean Free Wheeling Hubs not Swivel Hubs.
The heat can only come from the wheel bearings or the disc rotors and if it was too much preload on the wheel bearings it should be worse on the highway

Because it is when you are offroad and the brakes are working hard I would suspect it may be a proportioning issue and too much braking effort is going to the front rotors.
I have seen mine up over 60 (on a laser temp gun) once but nowhere near 80.

Even tho the issue was there before and after your Bearing rebuild I would double check the wheel bearing preload and then I would be looking at bleeding the brakes and ensuring the proportioning valve is OK. The valve is quite often a source of issues esp if it hasn't been reset correctly for lifts etc

yeah they are free wheeling hubs...doh! sorry about that. yes, I have taken it to Patrolapart to get it completely stripped down repacked with new seals and bearings. As for tensioning the bearings I haven't checked...figuring Patrolapart would have got all the settings correctly.

I have also bled the brakes (twice) post the new rotors and brake piston reconditioning. I will have to find out how to check the proportioning valve on the brakes.......dunno how to do that. The temperature was read using one of those laser thingys with the red dot....point and shoot for the reading.

Quote:

---

Originally Posted by 94patrol

snip... The temperature was read using one of those laser thingys with the red dot....point and shoot for the reading.

---

Yeah thats what I use... when towing I check my hub temps on the Patrol and my Van every major stop (smoko, lunch, fuel) when I do my walk around.
It immediately alerts me if one of the Van eleccy brakes is having issues (too cold) or I have a wheel bearing problem (too hot).

Brake proportioning valve - if you have a lift and it hasn't been adjusted then it thinks there is less weight in the rear and 'sends' more effort to the front.
They also get grunged up, corroded etc as the vehicle gets on a bit in years

yeah got a 2 inch lift in it. I gotta find out where the brake proportioning valve is....do you know where it is on a gq? I have jacked up the wheels a checked if the brakes were binding...nope. so, am stumped....

Quote:

---

Originally Posted by 94patrol

snip....do you know where it is on a gq?

---

Attached to the rear of the rear diff housing... has the rear brake lines going to it with a spring attached to the vehicle body.

Not saying it is 100% the issue but if you have a lift you can get/make an extension for the spring attachment to restore the correct brake bias

ok ta, I will have a look....is there anything in particular I should keep an eye out for?

I had a look and have located it....thanks for that. Other than the unit and all that goes with it covered in dust/dirt it looks like the factory original and no additional adjustments have been done. the only thing I did noticed was the adjustment screw where the arm pivots is not sitting on the arm. there is a bit of movement before the arm actually touches the adjustment screw (at least a couple of mm) The spring is tensioning the arm, meaning the surface of the arm and the head of the adjustment screw does not touch.

Quote:

---

Originally Posted by 94patrol

I had a look and have located it....thanks for that. Other than the unit and all that goes with it covered in dust/dirt it looks like the factory original and no additional adjustments have been done. the only thing I did noticed was the adjustment screw where the arm pivots is not sitting on the arm. there is a bit of movement before the arm actually touches the adjustment screw (at least a couple of mm) The spring is tensioning the arm, meaning the surface of the arm and the head of the adjustment screw does not touch.

---

Post a picture.

here is a picture of the rear brake proportioning valve...pls let me know what you think. many thanks againAttachment 74014

I read another thread about proportioning bracket and how to check if mine required such a bracket. After checking mine in relation to the thread I think it does need a bracket to allow for the lift as the spring is not 90 deg to the valve. Will look at making up a bracket as I have some scrap steel and then take the truck out for a test.

Quote:

---

Originally Posted by 94patrol

I read another thread about proportioning bracket and how to check if mine required such a bracket. After checking mine in relation to the thread I think it does need a bracket to allow for the lift as the spring is not 90 deg to the valve. Will look at making up a bracket as I have some scrap steel and then take the truck out for a test.

---

Yeah, that might be a good idea.

You can close that gap by turning the screw and see what happens when you brake.
I think it is related to the odd angle created by the lift.

I've never touched or adjusted the proportioning valve in mine, and it's about time I have a good look at mine as well.

thanks....will look at making a bracket today. shouldn't be too difficult. will post a picture when done.

dom14...you were correct to note that the gap was due to the lift with no bracket to compensate for it. Made the bracket, put it all back together and yup.....no gap. please find attached photos to show progress and end result.....now I will need to take the patrol for a drive and see.
Attachment 74028Attachment 74027Attachment 74026Attachment 74025Attachment 74023Attachment 74024

noticed the photos weren't in the order I had loaded...it's a bit jumbled

A quick word of advice just in case the temptation arises... do NOT blindly adjust that bolt on the proportioning valve.

Quick linky thingy that explains what it does... http://www.stoptech.com/technical-su...tioning-valves

hey....many thanks for the link....it certainly is a lot of information to digest. one good thing...I did not have to adjust anything at all. By making and installing the bracket it resulted in the adjustment screw to be back in plain with the arm. So I am absolutely happy with the end result. Have not had to chance to take the bus out for a drive...will probably do it this evening. will be looking out for stopping ability and of course the temperature in the free wheeling hubs. many thanks for all the help and information....couldn't have done it without all the invaluable feedback. will post the results soon. :thumbup:

been for a drive on both flat and hilly terrain. on the flat terrain and probably about 5 kms with normal stop/start the hubs were warm and totally acceptable. on the hilly section with both up and downhill sections the hubs got as hot as before (no significant drop in temperature). So, I am still at a loss to explain/resolve this heat retention in the hubs business.:confused:

Quote:

---

Originally Posted by 94patrol

been for a drive on both flat and hilly terrain. on the flat terrain and probably about 5 kms with normal stop/start the hubs were warm and totally acceptable. on the hilly section with both up and downhill sections the hubs got as hot as before (no significant drop in temperature). So, I am still at a loss to explain/resolve this heat retention in the hubs business.:confused:

---

Did you adjust the bearings?

The excessive heat can't be from free wheeling hubs mate (afaics). It must be from the bearings or the brakes.

When it's hot, put on pair of leather gloves & undo the wheel and investigate. It is from both wheels of the front, right?!
Binding or grinding brake is usually the most common cause, seconded by tight bearings.

yup, It's from both front wheels. I have jacked the wheels up and spun them. The breaks are not binding. I have checked superficially if it is the bearings by grabbing the wheels and rocking them....no play. I had the whole front done by Patrolapart, all the way back to the king pins only about 3 weeks ago.

Quote:

---

Originally Posted by 94patrol

yup, It's from both front wheels. I have jacked the wheels up and spun them. The breaks are not binding. I have checked superficially if it is the bearings by grabbing the wheels and rocking them....no play. I had the whole front done by Patrolapart, all the way back to the king pins only about 3 weeks ago.

---

Yeah, I believe ya, but as a general rule, I prefer to do my own checks as well.
Check the drag of the wheel by turning it, not the play. A slight play is not likely cause excess friction heat, but too much drag
will cause excess heat(and bearing damage).
The best time to check whether the brakes are binding (or the bearings are dragging) is when it is hot where you can't touch it
with bare hands.
I still think it can't be from the freewheeling hubs(unless there has been something really gone bad with them due to wear/bad service/ etc)

Heat in a rotating mechanism can only be generated by Friction.
Sooo lets work thru the whole front drive drive train.

Logic says it can't be the Brake Calipers dragging and they have been ruled out.
If it was then the Calipers will drag on and off road regardless of the FWH and the temps will be the same on and off road (or even hotter after belting up and down the bitumen at higher speeds).

Logic says it probably isn't the Wheel Bearings for similar reasons as the Calipers

Logic says it probably isn't the FWH themselves.
A FWH is simply a Dog Clutch so only has independently rotating and stationary parts when 'free'.
Even when packed with the incorrect or too much grease they don't get obscenely hot they just get hard to engage or chatter
That means a FWH would be hotter on the Bitumen because when 'engaged' all parts are stationary relative to each other

Sooo, logic says it must be something that is only introduced when the FWHs are engaged and/or 4WD so lets work thru them

Can't be the Transfer Box
Can't be the Front Drive Shaft or Uni Joints
Can't be the Axle Seals
I'd be amazed if the Front Diff could generate that amount of heat and for the heat to conduct out to the Hubs in that short a time and not be screaming like a banshee BUT it wouldn't hurt to check the Diff for ease of rotation and the diff pumpkin temp

Unfortunately that rules out just about everything mechanical 'cept the diff etc sooooo...

Jump under the vehicle with the Transfer case in 'neutral' or '2H' and the FWH in 'free' and see how much effort it takes to turn the front drive shaft by hand.
If you can turn it with reasonably little effort by hand then the diff should be OK

Which leaves Braking.
To fully rule out braking issues go and find a safe place (large empty Car Park or whatever) where you can simulate heavy braking.
Drive around the area at low speeds in 2H with the Hubs in 'free' say under 40 and do a series of light and some firm to heavy (not lock up) braking applications for 5 minutes or so.
If the Hubs are hot as beejesus then there must be some issues with the front braking effort

If the hubs are normal do the same thing with the Hubs 'locked' BUT leave the transfer in 2H.
If the Hubs are hot as beejesus after that then the issue is front diff/axle related

... uuummmm... I just reread your original post.

Can you confirm the hubs overheat in 2 and 4wd or is it only when doing tracks in 4wd?

ok....will jack up the wheels when they are hot and post results soon....I am scratching my head a bit....it shouldn't be that hard to figure it out

How is the diff oil? Is it up the fill plug when on a level surface. What condition is it in. Is there grease packed into the Constant Velocity joints? What condition is that in too?

I think the CVs and the diff would've gone kaput with enough noise before it would transfer a lot of heat to the FWH.

Ok.....I have rotated the drive shaft whilst in 2wd n neutral. Can turn the drive shaft effortlessly....I will do the carpark heavy stopping a little bit later. The hubs get hot in either two or 4wd situation. I first noticed this after a track drive when I tried to free the hubs. So I immediately thought it was my bearings but under load. Then post returning I checked it more vigilantly and it occurs in either situation. I had drained and renewed the oils, did all the basic checks and when it was still,occurring I took it to Patrolapart.

I have just double checked my diff oil level and for contamination. I can confirm it is at the correct level and not contaminated. Patrolapart services the front ends, both hubs and cvs. I am pretty certain the cvs will be packed with grease. I was advised they are in good knick.

So, that leaves two things left to check off, (a) the simulated heavy braking in 2wd n 4wd modes and (b) when HOT jack the wheels up to see if the brakes are binding.

If it does it in 2WD with the hubs disengaged that eliminates everything 'cept wheel bearings and brakes.
It can't be the CV's, Diff, Grease, Oils, FWHs etc etc

Maybe 80 degrees isn't that bad, maybe mine get that hot at certain times but I've not noticed.
Maybe your heavier on the brakes than me so my temps are a bad comparo.
I am old school, really old school, so I use engine and gears a lot for braking and double clutch when towing.
So much so that if I'm 'daily driving' around town my brakes get cold and I have to be wary as I'm running cold pads and slotted rotors for when I tow.

I have not had the chance to do the last two items yet...but I too, am old school....gentle on the pedal at all times and if I can coast to a stop with gentle braking or minimal....that's me. That was/is why I am concerned about the hubs getting hot as I do not stomp on the brakes. I will be carrying out the last two tests in the next day or so. Will post the results asap.

I did read somewhere that running bigger tyres does impact the cooling of the brakes. I am running 285/75 r16's

Running bigger tyres needs more braking effort as the lever is effectively longer so, yeah, does affect the pad and rotor temps.
There's a hell of a lot of people running 285/75r16 tho including me.
I used to run 315 until about 18 months back but dropped back to 285 as I now do more towing than gnarly 4X work
On my prev Patrol (ZD30 CRD) I ran 285 exclusively for 5 years

I've experienced FWHs getting hot to the point of not being able to touch it when going downhill for quite a distance while constantly using brake, and particularly true when the vehicle is auto.
Your is not an auto and it gets hot regardless of going downhill with constant brakes or not.
So, I reckon something's going on there.

I thought from the OP posts the hubs are only getting hot with hilly work in both 2X and 4X.

I am starting to think either the temps he is seeing are normal and there is nothing wrong... or maybe a gunked up or corroded BPV

I was thinking about the bpv. if the rear breaks are not working efficiently as they should be because of dodgy bpv then the front brakes will be working pretty hard to stop the patrol. that said, how do i check if the bpv is dodgy or had the gong?

Quote:

---

Originally Posted by 94patrol

I was thinking about the bpv. if the rear breaks are not working efficiently as they should be because of dodgy bpv then the front brakes will be working pretty hard to stop the patrol. that said, how do i check if the bpv is dodgy or had the gong?

---

Try bleeding it first. If a lot of black muck comes out of it then it may not have been bled for a while - if ever. If that is the case there is a good chance it is seized up.

Quote:

---

Originally Posted by 94patrol

I was thinking about the bpv. if the rear breaks are not working efficiently as they should be because of dodgy bpv then the front brakes will be working pretty hard to stop the patrol. that said, how do i check if the bpv is dodgy or had the gong?

---

Quote:

---

Originally Posted by the evil twin

I thought from the OP posts the hubs are only getting hot with hilly work in both 2X and 4X.

I am starting to think either the temps he is seeing are normal and there is nothing wrong... or maybe a gunked up or corroded BPV

---

Are the hubs only getting super hot in hilly work going down the hill as ET indicated above?

If that's the case, then you don't have a problem.
I've experienced my share of red hot hubs going down hill with constant braking.
You can even begin to lose a bit or brake as well 'cos once it get hot enough rotors and pads lose a fair bit
of friction as well. You can counter balance the situation by using a bit of engine braking in a manual gearbox,
but obviously not much of a choice with an auto tranny.

no, I have noticed it even on normal roads, say when there are lots of stops and starts (particularly this time of year). Mine a a manual td42 y60.

anyway, I have just bled the bpv. the initial flow was the dirty brown then followed by the colour of my current brake fluid (blue). so, i still need to conduct the last two tests and we shall see. will post results as soon as i have done the tests.

hi all, I did the test in 2wd along a quite industrial park. It does get hot when I stomped on the brakes quite a number of times. Will conduct the test in 2wd (hubs engaged but transfer case not engaged) tomorrow when hubs are cold and then will jack the wheels up and check for brakes binding whilst still hot.

tested it with hubs locked but transfer case not engaged....still gets hot....as noted by evil twin.....it may be that is the way it is....hubs clocking in at nearly 80 deg C when braking is involved. Thank you everyone for your helpful comments.