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The mkiv Supra Owners Club

Suspension refresh (wishbones etc) The results...


Ian C

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Over the past year or so the handling on my car has been degrading, in a subtle stretched-out-over-time-am-I-imagining-it fashion. Rear wheel steer, a bit of shimmying, snatching on lane changes, tramlining. No matter what I did with alignment, tyre pressures etc, it never quite seemed to be as good as I remember it being, and it was actually starting to make me not enjoy driving the car so much :(

 

By "handling" I mean how the car feels to drive full stop. Not just caning it round bends, but driving at 30mph in a queue of traffic on bumpy roads, or taking sweeping bends in DCs at 80mph, or wanging round roundabouts or changing lanes etc.. Pretty much all of it was affected by this, and it was nasty.

 

Then one dark rainy night on the way back from working late I anchored on to take a different route through the city and there was a big "clonk". Further experimentation gave me a big nasty clonk from the front on sharp braking and a creak as I subsequently let off the brakes.

 

This prompted me to take it in to SCA Race and Rally (http://www.sca-racerally.co.uk) as they are local, trustworthy, and do good suspension work. They showed me marks on the subframe mounting points where the front wishbones sit. These marks were caused by the wishbone bushes rubbing on the bracket, which is particularly disturbing as they should be sat about 3mm away! 3mm of random suspension travel, no wonder the car felt like it was all over the place! The suspension bushes were completely shot.

 

So, me being me I figured that if those ones are buggered, then all the others will be as well - no point in changing out half of the eleven year old bushes and expecting everything to get fixed. So I'll swap the lot.

 

The definitive parts list that I went for was:

Front:

48610-19025 Front Upper Arm - RH

48630-19025 Front Upper Arm - LH

48068-14080 Front Lower Arm sub assy - RH

48069-14080 Front Lower Arm sub assy - LH

 

Rear:

48730-14040 Rear Lower Arm - RH

48740-14070 Rear Lower Arm - LH

48710-14110 Rear Arm Assembly RH

48720-xxxxx Rear Arm Assembly LH

48780A Rod assy, rear

48780A Rod assy, rear

48725-14070 Bush, rear axle carrier 48725F RH

48725-14070 Bush, rear axle carrier 48725G LH

48770A Arm assy, Upper control, rear RH

48790 Arm assy, Upper control, rear LH

 

I got a quote off Steve Manley and it came to around £1700 +shipping :faint:

I then spoke to our man Nic in Hong Kong and the quote was substantially lower! The money side of it was a tad confused as I bought new wheels off Nic as well and paid for a shedload of air freight shipping, but it was a huge saving, well done Nic :D

 

OK some of you may now be blanching at the idea of spending £1200 on bits that are exactly the same as stock, not shiny, don't give you more power, and you can't even see them but bear with me ;) It actually gets worse so hold on. I figured that suspension components that have been on the car since the factory weren't going to be the easiest things to remove ever. Seeing as it's going to need a lot of 'right tools for the job' and a lot of swinging room, and get aligned afterwards by them anyway, I thought SCA could have it to do the job rather than me try it in the rain on the driveway without enough room under the car to oscillate a feline never mind use a breaker bar.

 

Turns out I made the right decision as it took two of them two days solid to sort it out :shock: The rear control arm (toe-in) bolts were so seized in the bearing housing of the bushes that they had to cut them off (the nut undid fine, just the bolt wouldn't physically come out!). The front lower wishbones were a nightmare of epic proportions, they even took an oxy cutter to one of them in an effort to get the inner housing to let go of the bolt. I'm strangely proud of that :) Bizzarely once the (undamaged) bolt was out it was perfectly OK to re-use :blink: it was just the sheer grip of the inner bush housing that was causing the problem.

 

Anyway. They knocked the labour rate down as much as they could but had to charge 12 hours, plus a few wrecked sawblades and angle grinder disks, and a full 4 wheel laser alignment = £850. High, certainly, but considering how much work it took and that includes £120 of alignment and £100 of materials, it's not so bad. They did a darn good job :)

 

So there you go, two grand lighter and my car looks like it did before the work. If you are still reading, well done :) Because IT DRIVES SO WELL!! SOOOOO WELL! Every single problem with the handling has gone :nana: It drives as smooth as the engine feels. It's still stiffly sprung but I feel the road instead of being chucked around by it, and it doesn't feel like I'm about to get thrown into the nearest hedge at any moment. The car feels nailed to the floor again. It's like a new car. I can't emphasise how much difference it's made! It's nothing I can datalog (for once!) so you're just going to have to rely on me waffling on here :)

 

So if you've got squiffy handling, rear end steering (and I know there are a few of you out there...) or any other nasties - bear in mind your suspension is how old? Get this done. Get the bits off Nic. Cross your fingers that it'll be an easier job to get the old stuff off. Spend about £1500 to £2000 on this instead of chrome 20” alloys and get a total rejuventation of how your car feels. Do it if you like driving your car - you track day fiends and 'ring addicts would certainly benefit. Everything feels so tight, taught, and "right".

 

Oh and did I mention I got new wheels too, have a piccy, I like them :D Me, doing external mods shocker. Well they are easier to clean and lighter so it was entirely practical :innocent: My old 18's will be up for sale with tyres on (Pirelli P0's) he said, unashamedly pimping stuff for sale in tech :thumbs: :D

 

Also find attached a piccy of the recalcitrant old suspension!

 

-Ian

newwheels2_sml.jpg

suspension_old1_sml.jpg

suspension_old2_sml.jpg

suspension_old3_sml.jpg

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Dunno what happened to the piccies, they are up now :)

 

Mine is a '96. 70k miles on the clock, but tbh it was shagged at about 65k. Relatively low mileage but I have quite hard suspension and the car has gone over a lot of crap bumpy roads in Norfolk over it's years so that's probably accelerated the wear more than normal.

 

I personally wouldn't swap just the bushes for aftermarket ones because a) you can't refit sawn up wishbones lol and b) it'd be even more labour cost as you'd have to press the bushes out and in again, so what you save on suspension components off Nic you'd pay in labour. And your ball joints etc wouldn't get replaced in the process :shrug:

 

-Ian

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I'd love to have the money to do this. I'm going to print it out anyway just in case.

 

So, Ian, we'll be expecting good things on the handling circuit on Sunday then, yeah?

 

I didn't upgrade the nut behind the wheel sadly, I think that one has well and truly siezed.

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Good write up Ian

 

Having spent money on the front and rear poly control arm bushes and still having the uninspiring drive i bit the bullet a couple of months ago and bought the same parts you mentioned above.

 

It is sat here waiting to go on, when i get a chance Mr Wilson will be doing the work for me.

i replaced the dampers for some OEm bilsteins about 6k ago and I am very much looking forward to a confident driving experience again :) something that has been lacking for a while now. my car has done 96 k.

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Get someone to drive the car at fast walking pace and hit the brakes hard, whilst you watch the front wheels relative to the wheel arches. Be prepared to be saddened and to get the wallet out. Tired front suspension on the MKIV is evident on all but the newest, lowest mileage cars. Big rims with low profile tyres kills it even faster. Nice post Ian, I said it would be worthwhile. You can see now why I put caveats in pricing for suspension alignment and renewal, seized adjusters and through bolts are killers in terms of time and hassle.

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Get someone to drive the car at fast walking pace and hit the brakes hard, whilst you watch the front wheels relative to the wheel arches. Be prepared to be saddened and to get the wallet out. Tired front suspension on the MKIV is evident on all but the newest, lowest mileage cars. Big rims with low profile tyres kills it even faster. Nice post Ian, I said it would be worthwhile. You can see now why I put caveats in pricing for suspension alignment and renewal, seized adjusters and through bolts are killers in terms of time and hassle.

 

 

Expect an e mail in a couple of Days Chris for the above mentioned parts to be fitted :D

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Interesting you should post this. I was thinking of doing the same sometime soon as I'm getting some creaks from the rear and the handling isn't as tight as it used to be. My car is a bit newer (jun 97) but has done a few more miles.

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Ian,

 

Can you keep a tab on tyre wear for us please?

 

Do you think that a lack of jiggling about etc etc with have a positive effect on tyre life?

 

Probably not to be honest, as the issue is the wheels sitting still and the car shifting around on top of them.

 

However, a knock-on benefit is that the alignment has been set up and finally could be set up 100% within factory specs rather than on the ragged edge of tolerance and it being almost immediately out of alignment after the first bump :)

 

My tyre wear was always quite good, the rears always wore the centre out faster even at 28psi, the fronts wore evenly at 34psi. I've set the pressures to that as it's what I'm used to so any change in wear patterns can be attributed to the change in geo.

 

-Ian

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Guest Chumpalot

Good write up that. Has certainly given me some 'food for thought'. Perhaps I'll cancel christmas this year and treat myself instead :sly:

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Nic actually did a similar suspension replacement I think? It would be good to get his view. I think Paul Whiffin did the same on his car.

 

Nic was actually the main proponent of this for some time :) After the results he had, he mentioned it a few times be he ain't a eloquent as me, innit :p

 

TBH I was skeptical at first because I thought "why replace the metal bits for crying out loud" but as you can't get the bushes and they are sorta special somehow and so forth, and after the magic it's worked on the car, I finally understand :D

 

I guess people who have a jiffly rear end don't want to hear that they need to spend £2000 to fix it when fannying about with tyre pressures or shocks is mooted as an option as well :shrug: and fair enough, I bloody didn't want to hear it either - the suspension physically shifting around 3mm in various directions got through my defenses though ;)

 

-Ian

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Did your Garage re-do the geometry setup?

 

I used this bloke, Tony in Watford:

http://www.wheels-inmotion.co.uk

 

 

Has some good read-up:

THEORY

 

Camber Angle Theory

Camber Angle Basics

Drifting

Geometry Theory

Kingpin Inclination Angle Theory

KPI Included Angle Basics

Longitudinal Castor Angle Theory

Maintenance and Ride Height Basics

Pre-alignment Assessment Guide

Sequential Alignment Fault Diagnostics

Steering Geometry Theory and Axis Deviation Theory

Tracking or Wheel Alignment Basics

Vehicle Dynamics Consultation

Wheel Toe-In and Toe-Out Theory

Wheels Alignment Systems

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Nic actually did a similar suspension replacement I think? It would be good to get his view. I think Paul Whiffin did the same on his car.

 

Yes I completely overhauled my suspension a few years ago, including all new arms, shocks and wheel bearings. Not a cheap job, but definitely the best money I have spent on my car.

 

I was in a similar situation to Ian before the overhaul, the fun had gone out of the driving, as the handling had become so vague. The thing was, it wasn't an overnight thing, it had gradually gotten worse over a couple of years and like Ian, I was wondering if I was imagining that the handling had been better before of not :conf:

 

I was shocked after the overhaul just what a difference it made, as it highlighted just how badly the handling had gotten without me realising for so long. The difference was amazing, everything felt so smooth, tight and precise, as though it had just rolled out of the showroom.

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  • 5 weeks later...

I have just dug this tread out of the search, having missed it first time round.

 

Did it really make that much difference??

 

This is the last bugbear on my car.. I want it planted and smooth.

 

CW is putting his sus kit on it soon, I have new 18" stock offset wheels coming, so I will see what difference that makes.

 

I did change all the front bushes for poly on my last car and although it was a ball ache, with the right tools and know how it is something that can be done; taking your time being the key.

 

my question is.. Was there ever any concencous about aftermarket poly bushes that are a good fit and quality?

 

I know CW said that most poly kits were a total waste of time.

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I'll try the suspension frist. My front lower wishbones are poly already.

 

Mike, I think for you lightweight wheels and new OEM bushes will make all the difference.

 

Seeing as you metion it, how lightweight is lightweight?; what's the acceptable weight for a performance forged 18" wheel?

 

I have seen some non forged up to 25kg plus per wheel.

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