Diagnose my suspension issues and suggest a solution please
Discussion
After a 'spirited' drive around the New Forest I have decided the rear suspension on my 350 might need some TLC. I shall describe the things I think seem wrong and what I think might fix them and then you guys who actually know what you are talking about can laugh at my ignorance amnd tell me what I should really do.
Symptom 1) On undulating roads the suspension sometimes bottoms out and the tyres rub against the bodywork.
Cure 1) Fit longer or stiffer springs.
Symptom 2) On undulating roads the suspension gets very 'floaty'. This is most obvious over crests by even on just slightly bumpy tarmac it seems the suspension isn't keeping the tyres properly on the road.
Cure 2) Fit new shocks.
Symptom 3) The back end skips sideways when cornering on fast sweeping bends. Possibly related to point 2
Cure 3) Fit new underpants
If you can recommend shocks and springs (or what ever is needed) I will sort out new underpants. Looking out the side window to see where you are going at about 70mph is a little more exhilarating than I needed this afternoon. Mind you, I felt like a God when I caught it and turned a crash into a long drifty tail slide around the bend.
Symptom 1) On undulating roads the suspension sometimes bottoms out and the tyres rub against the bodywork.
Cure 1) Fit longer or stiffer springs.
Symptom 2) On undulating roads the suspension gets very 'floaty'. This is most obvious over crests by even on just slightly bumpy tarmac it seems the suspension isn't keeping the tyres properly on the road.
Cure 2) Fit new shocks.
Symptom 3) The back end skips sideways when cornering on fast sweeping bends. Possibly related to point 2
Cure 3) Fit new underpants
If you can recommend shocks and springs (or what ever is needed) I will sort out new underpants. Looking out the side window to see where you are going at about 70mph is a little more exhilarating than I needed this afternoon. Mind you, I felt like a God when I caught it and turned a crash into a long drifty tail slide around the bend.
Sounds like shock failure with possibly bad geo. Also worth checking your tyre pressures. Your bushes could also be worn. Jumping sideways tends to be poor contact between tyre and road or at certain point of compression of the suspension the toe in becomes to out!
Edited by MPETT on Thursday 22 December 15:40
Think standard springs at the back are ok for fast road use.
On mine with standard springs (kept the ones that were on the car) and gaz adjustable (platform and damping) shock absorbers, the road holding is very good (and better than my capabilities). Even on the odd track day the rear is very stable and only lets go due to the driver...
With the adjustable platform I was able to lift it a bit to avoid tyres hitting the body.
Experimenting with the damper settings of the rear showed that a softer setting has better grip.
Bushes have an impact as well, and if too bad the rear geometry could become 'self steering' or under extreme circumstances make the rear unstable.
And if the rear tie bar is not ok, the rear will become dangerous!
Diff carrier to be ok, if not the whole rear suspension is malfunctioning.
Tyres (old, bad quality, wrong rating) should be ok.
So first have look at the rear tie bar, bushes, state of the shocks, and check if the diff carrier is in one piece (couple of weeks ago there was a post about this) and take it from there.
Rob
On mine with standard springs (kept the ones that were on the car) and gaz adjustable (platform and damping) shock absorbers, the road holding is very good (and better than my capabilities). Even on the odd track day the rear is very stable and only lets go due to the driver...
With the adjustable platform I was able to lift it a bit to avoid tyres hitting the body.
Experimenting with the damper settings of the rear showed that a softer setting has better grip.
Bushes have an impact as well, and if too bad the rear geometry could become 'self steering' or under extreme circumstances make the rear unstable.
And if the rear tie bar is not ok, the rear will become dangerous!
Diff carrier to be ok, if not the whole rear suspension is malfunctioning.
Tyres (old, bad quality, wrong rating) should be ok.
So first have look at the rear tie bar, bushes, state of the shocks, and check if the diff carrier is in one piece (couple of weeks ago there was a post about this) and take it from there.
Rob
1) Have I got the right bits labelled correctly?
2) How can I tell if the shock is shot?
3) How do I tell if the bushings have had it and are they the bushings for the fron link, the rear link or both?
Just Googled that the AVO shocks are rebuildable (yippee) then Googled to find out how and found this thread http://www.pistonheads.com/gassing/topic.asp?h=0&a... (boo)
Anyone know if they are rebuildable and if it is worth it?
Forgot to mention on the original post that after a couple of crests the car did bottom out if that helps at all
2) How can I tell if the shock is shot?
3) How do I tell if the bushings have had it and are they the bushings for the fron link, the rear link or both?
Just Googled that the AVO shocks are rebuildable (yippee) then Googled to find out how and found this thread http://www.pistonheads.com/gassing/topic.asp?h=0&a... (boo)
Anyone know if they are rebuildable and if it is worth it?
Forgot to mention on the original post that after a couple of crests the car did bottom out if that helps at all
Edited by wca on Thursday 22 December 17:49
Hi mate..If the rear end feels like it is wobbling from side to side over bumps then it sounds like the half shaft UJs need replacing..This was happening to mine a little while back..I think you might be able to feel the movement by rocking the rear wheels in and out whilst jacked up to feel for any excessive play..There are two on each shaft, Also they are not an easy fix!!..Doable with the right equipment but can be a right pain..If your car has trailing arm suspension then it could be the mounts that have failed..It could be both as was mine..Ziga
Hi Nick
You car has trailing suspention rear end.
First i would uave a look at the diff mount for damage cracks as they are made of alloy or movement.
Second have a really good look at the front mount of the trailing arm for deteriation rubber flacking off most likely done in...
Thurd check the other bushes on the rear tie rod and the bottom shock mount and your shocks look ajustible platform and gass pressure, use wd40 on the ajuster and see if it will turn. If its not been used for some time there is a good chance it could be sezed...if not count the clicks clockwise on both sides so you can reset back to what you have been driving at the mo. If the move try setting at half way and take for a drive.
Forth check the drive shaft ujs for any play this will move the wheels around and also check bearings and check the large nut is tight realy tight but if the bearings have any play at all checked with the wheel on then the bearing is shot.
It would proberly best to have all bushes done then have the tracking done...
Good luck.
Cambelt
You car has trailing suspention rear end.
First i would uave a look at the diff mount for damage cracks as they are made of alloy or movement.
Second have a really good look at the front mount of the trailing arm for deteriation rubber flacking off most likely done in...
Thurd check the other bushes on the rear tie rod and the bottom shock mount and your shocks look ajustible platform and gass pressure, use wd40 on the ajuster and see if it will turn. If its not been used for some time there is a good chance it could be sezed...if not count the clicks clockwise on both sides so you can reset back to what you have been driving at the mo. If the move try setting at half way and take for a drive.
Forth check the drive shaft ujs for any play this will move the wheels around and also check bearings and check the large nut is tight realy tight but if the bearings have any play at all checked with the wheel on then the bearing is shot.
It would proberly best to have all bushes done then have the tracking done...
Good luck.
Cambelt
Easy way to check whether your shocks are shot is to put pressure on that corner by leaning on it, if it leans down more than other shocks it's most likely leaking or shot... They look like they're old shockies tho!
Also check driveline, and all the bushings which could well be worn out.
My previous card had worn out rear sway bar bushings and that made it skip about on uneven roads like mad. A suspension rebuild is always a good idea if you want to keep the car in tiptop shape though! Especially if you don't know how old it all is.
Also check driveline, and all the bushings which could well be worn out.
My previous card had worn out rear sway bar bushings and that made it skip about on uneven roads like mad. A suspension rebuild is always a good idea if you want to keep the car in tiptop shape though! Especially if you don't know how old it all is.
vampire222 said:
Easy way to check whether your shocks are shot is to put pressure on that corner by leaning on it, if it leans down more than other shocks it's most likely leaking or shot...
That won't check the shock (damper): the usual way is to bounce each corner down hard and see how the car responds. If it comes back up and stops bouncing the damper is OK; if it carries on bouncing the damper is U/S (it's supposed to stop the bouncing!).However if the damper rod is bent (usually due to impact) the car may stay stuck in the 'down' position. Usually the forces involved will shag the seals so as you say, the damper will leak.
I've never been impressed with AVOs; they were fitted to my Esprit and even though they'd only been on the car a year before I got it (and it had been sat with no tax for half of that) they were corroded to hell. The adjustable spring platforms (as yours have) were extremely hard to adjust; it didn't help that they'd been wound up so far the car looked like a dragster. You may find some improvement by altering the platforms (and thus the ride height).
The trailing arm is prone to failure of the forward mounting bush: have a look at that for a start.
Missed out on your wedge being of the trailing arm rear suspension type. The tie rod I mentioned is on the A-frame.....
Trailing arm setup is known for being limited at maximum suspension positions (the alignment changes then too much), therefore the later A-frame used for racing and wedges with a lot more power, and installed on all models from somewhere at the end of 1985 onwards. As mentioned before the u-joints are important, but also the mounting of the trailing arm where it swivels (most front point). There is a bolt and a rubber, which if not ok will wreck the handling.
So perhaps you just experienced the behaviour of the trailing arm suspension at its limit.
Seems you have platform adjustable shocks with adjustable damping and perhaps it is worth experimenting with them.
Shocks can be tested at a kwikfit etc.
Rob
Trailing arm setup is known for being limited at maximum suspension positions (the alignment changes then too much), therefore the later A-frame used for racing and wedges with a lot more power, and installed on all models from somewhere at the end of 1985 onwards. As mentioned before the u-joints are important, but also the mounting of the trailing arm where it swivels (most front point). There is a bolt and a rubber, which if not ok will wreck the handling.
So perhaps you just experienced the behaviour of the trailing arm suspension at its limit.
Seems you have platform adjustable shocks with adjustable damping and perhaps it is worth experimenting with them.
Shocks can be tested at a kwikfit etc.
Rob
One thing that i dont think has been mentioned (unless ive missed it) if those rear shocks are adjustable make sure they are both adjusted the same. My 450 had an issue with the rear nearside tyre catching on the arch on bumpy roads and the handling was err....interesting due to the fact that the damping/rebound on each shock was adjusted differently along with the ride height, presumably to try and compensate for the catching. It also had old remoulds on the back!!!
Now i have proper tyres, new springs and correctly adjusted dampers it is a different car and that's before i have the 4 wheel alignment done in the spring.
Remember it is a relatively light car so if adjusted to firm on the rear it will bounce around on poor road surfaces thus affecting the tyres contact with the road. I speak from experience.
Drive it. Play with it. Adjust it. Drive it..................................etc
Its all part of the fun!
Jimbo
Now i have proper tyres, new springs and correctly adjusted dampers it is a different car and that's before i have the 4 wheel alignment done in the spring.
Remember it is a relatively light car so if adjusted to firm on the rear it will bounce around on poor road surfaces thus affecting the tyres contact with the road. I speak from experience.
Drive it. Play with it. Adjust it. Drive it..................................etc
Its all part of the fun!
Jimbo
I will be sticking new tyres on it. The current ones are old and are more like plastic than rubber.
I will get a local tyre place to check the state of the shocks.
How do I adjust them?
There is a dial at the bottom for rebound but do I need some special spanner to move the spring mount up and down the thread?
i guess moving it down the thread shortens the spring lowering the car and making the ride softer while moving it down lowers the car, right?
~EDIT : Just had the car checked at local tyre place. Shocks appear okay but bushings are shot. Time for new poly bushes all round I guess. Any recommendations?
I will get a local tyre place to check the state of the shocks.
How do I adjust them?
There is a dial at the bottom for rebound but do I need some special spanner to move the spring mount up and down the thread?
i guess moving it down the thread shortens the spring lowering the car and making the ride softer while moving it down lowers the car, right?
~EDIT : Just had the car checked at local tyre place. Shocks appear okay but bushings are shot. Time for new poly bushes all round I guess. Any recommendations?
Edited by wca on Saturday 24th December 10:15
wca said:
I will be sticking new tyres on it. The current ones are old and are more like plastic than rubber.
I will get a local tyre place to check the state of the shocks.
How do I adjust them?
There is a dial at the bottom for rebound but do I need some special spanner to move the spring mount up and down the thread?
i guess moving it down the thread shortens the spring lowering the car and making the ride softer while moving it down lowers the car, right?
~EDIT : Just had the car checked at local tyre place. Shocks appear okay but bushings are shot. Time for new poly bushes all round I guess. Any recommendations?
Yes tenner a pair on ebay for the shock spanners. The dial on the shock should have around 23/24 clicks. Clockwise stiffens it up, anti-clockwise softens it. Wind both right back anti-clockwise until they stop-DON'T force the dial once you get some resistance. Once wound back then turn clockwise and experiment with the damping rate ensuring both sides are the same. The dials can be adjusted with the car on the road and not on jacks/ramps so you can go for a spin, adjust, drive again and so on.I will get a local tyre place to check the state of the shocks.
How do I adjust them?
There is a dial at the bottom for rebound but do I need some special spanner to move the spring mount up and down the thread?
i guess moving it down the thread shortens the spring lowering the car and making the ride softer while moving it down lowers the car, right?
~EDIT : Just had the car checked at local tyre place. Shocks appear okay but bushings are shot. Time for new poly bushes all round I guess. Any recommendations?
Edited by wca on Saturday 24th December 10:15
Obviously if the bushes are to be replaced there's no point in doing this until they are done.
Jimbo
wca said:
Time for new poly bushes all round I guess.
Hi Mate..Poly bushes are treble the price compared to normal rubber bushes..They are ok if you are going to be going on track days but there are no real benefits other than that..When i put mine into dan taylor TVR and inquired about replacing my bushes with poly bushes he asked why..The ones that were originally fitted have lasted 30 years..Like he said " If you are considering track days by all means use poly bushes but for normal road use why pay out all that money for something that might not last as long as something the third of the price "..The choice ultimately is yours..ZigaOkay, I think I know what I need. The red bit in the picture is this http://www.ebay.co.uk/itm/TVR-WEDGE-TASMIN-REAR-TR... I think.
Can anyone post a link showing where I can buy the blue bit? There seem to be lots of places selling various bushes but nothing called "025D O10A BUSH - LOWER SUSPENSION LINK" which is what I think the blue bit is called in the manual I have.
I have found this : http://www.ebay.co.uk/itm/TVR-Wedge-Classic-SUPERF...
But don't think it is what I want. Any help appreciated.
EDIT
Just raised the rear suspension an inch and what a difference!! All of the clonking has disappeared and no bottoming out or nasty noises under acceleration. I think is must have been set way to low. No noticeable wobble in the wheels when they were jacked up so hopefully the UJs are okay. No obvious cracks of damage underneath although I am not certain what I was looking for.
Car still squirms when pulling out of corners and more on the left than the right so I guess I still need bushes.
Can anyone post a link showing where I can buy the blue bit? There seem to be lots of places selling various bushes but nothing called "025D O10A BUSH - LOWER SUSPENSION LINK" which is what I think the blue bit is called in the manual I have.
I have found this : http://www.ebay.co.uk/itm/TVR-Wedge-Classic-SUPERF...
But don't think it is what I want. Any help appreciated.
EDIT
Just raised the rear suspension an inch and what a difference!! All of the clonking has disappeared and no bottoming out or nasty noises under acceleration. I think is must have been set way to low. No noticeable wobble in the wheels when they were jacked up so hopefully the UJs are okay. No obvious cracks of damage underneath although I am not certain what I was looking for.
Car still squirms when pulling out of corners and more on the left than the right so I guess I still need bushes.
Edited by wca on Monday 26th December 12:37
Edited by wca on Monday 26th December 12:37
Hi mate..If you are replacing the trailing arm pin mounts then it is normally good practice to change the trailing arm pins as well as they do rust in place and often can get bent or have to have the nut cut off to remove..The pins and mounts should really be changed on both sides at the same time to make sure there is equally movement or the older one could fail and then you are back to doing it all again..Richard Thorpe racing..(RT Racing).. have manufactured trailing arm pins and they cost £19.95 + vat ea and the mounts were £24 + Vat ea..Its about £45-50 per side..He should also stock the lower rear suspension bushes..Give them a call they are very helpful..Ziga
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