GU Y61 Suspension Questions - Please Help

[HankyBoii]

Hi all,

I'm totally new to suspension and just trying to wrap my head around all the different components and their functions.

I have a few questions to ask you all... any help is greatly appreciated.

Context: I bought a 2004 GU Y61 Patrol about 2 years ago. It has always been a harsh ride, you feel every bump in the road and on longer drives, you get a sore lower back from the jarring bumps. The previous owner claimed the car was setup for towing and he thinks he installed 2" lift springs which he claims are 300-400kg springs. I'd really like to improve the drivability of the car, as I am about to start on my lap around Australia. 99% of time it will be used on-road, however we do like to go off-road occasionally for a bit of fun (nothing serious).

The Springs: I don't know what are on the car at the moment, there are no part numbers or markings on them. I did some research and found that you can measure your ride height to figure out what springs are installed... here is the data:

Stock GU Values (Center of wheel to guard):
Front 550mm
Rear 560mm

Measured on my car (Center of wheel to guard):
Front 580mm
Rear 540mm

Not too sure what to make of this??

Shocks: My car has upgraded shocks, they are:

Front - Toughdog FC41047 - LINK (https://suspensionmegastore.com.au/product/td-fc41047-tough-dog-41mm-foam-cell-shocks/)
Rear - Toughdog FC41206 - LINK (https://suspensionmegastore.com.au/product/td-fc41206-tough-dog-41mm-foam-cell-shocks/)

Looks like they are suitable for up to 2" lift

Additional Info: I just recently found a pair of front and rear 2" King Springs on marketplace for cheap. I got a set of KDFR-42HD front springs and KDPR-58LP rear springs which I'd like to put on my car to replace the current setup.

It also seems like I have upgraded toughdog steering dampner too... not sure if panhard has been replaced, but I do get a noticeable wobble at around 80kmph.

Weight of car: Fully loaded with 2 people and all our stuff we weigh in at 3.1T

Accessories on the car are as follows:
- Stock alloy bar and stock rear bar
- Second battery
- 95kg Roof top tent
- Kings drawers with tools and other camping essentials
- Removed rear seats and put in a wooden tub for storage
- Rear of car loaded with plastic tubs with clothes, shoes, fishing gear and cooking gear

Questions:

Will replacing the current springs with the king springs make much of a difference?
Do you recommend I upgrade the shocks at the same time, or are these ok for my needs?
I feel like due to either additional weight or spring sag, the rear of the car is hitting the shocks bump stops, do you think this may be the case?
Could something else be causing this very hard ride?
Will I need anything in addition, for example caster correction, extended brake lines, etc.. if I replace the current springs with the new ones?
Anything else you would recommend me to check for before doing my lap?



Thank you in advance!

[PeeBee]

Well thats a very comprehensive post there HankyBoii. I am sure some quality feedback will flow.

[TPC]

My GU has an OME Suspension 2 inch lift and front is 560mm from wheel centre to guard and back is 590, it has steel bulbar and dual batteries at front and drawer system at back.

[Plasnart]

Hi all,

I'm totally new to suspension and just trying to wrap my head around all the different components and their functions.

I have a few questions to ask you all... any help is greatly appreciated.

Context: I bought a 2004 GU Y61 Patrol about 2 years ago. It has always been a harsh ride, you feel every bump in the road and on longer drives, you get a sore lower back from the jarring bumps. The previous owner claimed the car was setup for towing and he thinks he installed 2" lift springs which he claims are 300-400kg springs. I'd really like to improve the drivability of the car, as I am about to start on my lap around Australia. 99% of time it will be used on-road, however we do like to go off-road occasionally for a bit of fun (nothing serious).

The Springs: I don't know what are on the car at the moment, there are no part numbers or markings on them. I did some research and found that you can measure your ride height to figure out what springs are installed... here is the data:

Stock GU Values (Center of wheel to guard):
Front 550mm
Rear 560mm

Measured on my car (Center of wheel to guard):
Front 580mm
Rear 540mm

Not too sure what to make of this??

Shocks: My car has upgraded shocks, they are:

Front - Toughdog FC41047 - LINK (https://suspensionmegastore.com.au/product/td-fc41047-tough-dog-41mm-foam-cell-shocks/)
Rear - Toughdog FC41206 - LINK (https://suspensionmegastore.com.au/product/td-fc41206-tough-dog-41mm-foam-cell-shocks/)

Looks like they are suitable for up to 2" lift

Additional Info: I just recently found a pair of front and rear 2" King Springs on marketplace for cheap. I got a set of KDFR-42HD front springs and KDPR-58LP rear springs which I'd like to put on my car to replace the current setup.

It also seems like I have upgraded toughdog steering dampner too... not sure if panhard has been replaced, but I do get a noticeable wobble at around 80kmph.

Weight of car: Fully loaded with 2 people and all our stuff we weigh in at 3.1T

Accessories on the car are as follows:
- Stock alloy bar and stock rear bar
- Second battery
- 95kg Roof top tent
- Kings drawers with tools and other camping essentials
- Removed rear seats and put in a wooden tub for storage
- Rear of car loaded with plastic tubs with clothes, shoes, fishing gear and cooking gear

Questions:

Will replacing the current springs with the king springs make much of a difference?
Do you recommend I upgrade the shocks at the same time, or are these ok for my needs?
I feel like due to either additional weight or spring sag, the rear of the car is hitting the shocks bump stops, do you think this may be the case?
Could something else be causing this very hard ride?
Will I need anything in addition, for example caster correction, extended brake lines, etc.. if I replace the current springs with the new ones?
Anything else you would recommend me to check for before doing my lap?



Thank you in advance!

Hi Hank, please put up an intro and let us get to know you a little.

1. You’ve got a rooftop tent, heavy, and rear drawers, heavy. Previous owner “thinks” he did a suspension upgrade. Fact: previous owner did not. You are hitting bump stops with original springs. Chuck the Kings in.
2. Depends on condition. King springs are suited nicely with Koni shocks.
3. See 1.
4. What tyres are you running? Low profiles will shake your fillings out. What pressure are you running? Get some good 70/75% sidewall tyres and learn when to pump up tight and when to air off softer. Different conditions/scenarios require different pressures (yes that’s a thing with 4x4s).
5. Generally not for 2” but best practice would say yes.
6. If you’re not experienced with 4x4s book in with a good 4x4 shop for a complete pre-trip check. If you’re staying on the bitumen you won’t get into too much trouble but if you’re going remote you need to know the ins and outs of it and be super conservative.

[MudRunnerTD]

Dump the Tough Dogs mate. Horrible bloody things IMO.

if you have a mate that you can borrow some shocks from then see if that makes a difference.

The Shock dampens the spring in both directions, dampening the spring at impact (down) can be really harsh and thats what you are feeling with your rough ride.

Honestly, if you are shopping to fix Springs are pretty cheap too, id start again. If you were a bigger lift then all the other items add in but for a 2" lift you are only talking springs and shocks. Easy fix. buy a matched set from someone that knows what they are talking about. You could spend fair bit of money trying to solve 1 item at a time of just cop it and replace. Sell the current lift on FB marketplace.

[MudRunnerTD]

Sorry i didnt read your final list.

1. Replace Springs and Shocks.
2. Kings and Konis will be fine. I like the Old Man Emu from ARB in my GU, they did 300000kms without missing a beat. I wanted to upgrade but the bloody things still stand tall and plush.
3. It wont be hitting the Shock bump stops, you would only do that once and the shocks would be knackered and leak everywhere. The bump stops on the back of a GU are mounted to the chassis in the top of the wheel arch. Refer to answer 1.
4. Not Really. If it is harsh through the steering wheel your caster may be out a little.
5. You may need some minor caster correction once a fresh 2" kit goes in, Maybe. If you think you are going to use the car for big articulations stuff then swapping the rear brake hose to the front and adding a new rear longer hose is a good thing.
6. Replace all engine hoses and belts and keep the old ones as spare. Dont take new ones as spares just in case and run the old hoses and belts. Just in Case ins very likely to happen at the most inconvenient time. Fit new, carry old stashed in the rear quarter panel behind the jack.

[HankyBoii]

Hi Hank, please put up an intro and let us get to know you a little.

1. You’ve got a rooftop tent, heavy, and rear drawers, heavy. Previous owner “thinks” he did a suspension upgrade. Fact: previous owner did not. You are hitting bump stops with original springs. Chuck the Kings in.
2. Depends on condition. King springs are suited nicely with Koni shocks.
3. See 1.
4. What tyres are you running? Low profiles will shake your fillings out. What pressure are you running? Get some good 70/75% sidewall tyres and learn when to pump up tight and when to air off softer. Different conditions/scenarios require different pressures (yes that’s a thing with 4x4s).
5. Generally not for 2” but best practice would say yes.
6. If you’re not experienced with 4x4s book in with a good 4x4 shop for a complete pre-trip check. If you’re staying on the bitumen you won’t get into too much trouble but if you’re going remote you need to know the ins and outs of it and be super conservative.

Thanks mate, my tyres are Toyo Open Country M/T LT285/75R16, I usually run them at around 35psi for on-road and drop them down to 25 for off-roading.