Chassis rear sus mountings shot.

[trickjohn]

Hi all,

I am currently refurbishing my s3 - whilst scrapping off the old plastic coating around the rear suspension mounting points (Welded on to the large lower rear outrigger support), i noticed that they looked corroaded therefore i gave them a large prod with a screwdriver they look thin and i think that they need to be replaced (one side only), as i was hoping to get away with a partial lift to repair the outriggers.

Has anyone replaced the brackets and if so, could they advise me -

Does the body need to be completely removed (I think I know what the answer to that is - bugger and blast)

Has anyone got the dimensions for the brackets?

Thanks in advance for any help

[trickjohn]

Hi all,

As I have had no replies, I take it this is a nasty one, so after having a good think about it. This is what I am going to do.

1) Remove the body (I would rather chew my arm off).
2) Measure the bracket form and position on the lower beam with a portable 7 axis 3D measuring machine linked to a CAD machine so I can reverse engineer the new brackets (3 pieces of material welded together).
3) Make a fixture that locates on the good bracket face and bore (0.02mm clearance) which will guarantee the distance between the faces and with a sliding locking spigot located in the opposite bracket bore which will guarantee the concentricity of the new bracket.
4) Remove old bracket (gently saw off so I dont shift the holding fixture.
5) Tack on the new bracket and confirm the position is correct (within 0.1mm) with the 3D measuring machine. Make any minor adjustments with a whopping great hammer.

If anyone has a better idea or can improve on the above please let me know.

PS When I was looking at peoples previous photos of body off rebuilds I noticed that they have anti roll front steering bars - mine doe not - any ideas where I can get one from, new or second hand my car is an s3 produced sold sept 1990 - looking at the vin number I am sure I need the last revolution of torsion bar.

Thanks in advance for any help or advise.

[Ray S]

Hi Sean can't help you with S3 bits as I have an S1.It's quite easy to do a partial body lift but if you have rot that bad on brackets you need to look over the rest of the chassis very carefully I found more than I bargained for on mine.Be careful that close to the tank.

[Barkychoc]

I would guess that the geometry would be hard to get right if you replaced the rear suspension mounts.
I am assuming it is the main tube that the mountings are on that is rotten?

I would be tempted to try and weld new metal over the top - not sure how feasible it is as I am no welder.
Could you get a piece of larger tube, cut it into 2 semicircle tubes then make cutouts for the brackets etc and weld it to it?
I'm making this up so tell me if I am talking garbage.

The other thought I had is to weld metal struts onto the suspension mounts to hold them in position - I'm thinking struts from the main chassis rails to the suspension mounts. (Multiple struts to hold them rock steady).
Them carefully cut away the mounts from the main tube - leaving the mounts in their original position held by the new struts.
Weld in new tube, re-weld the brackets back to the tube then cut away the struts that were holding the brackets in position.

I don't have any idea if this is feasible, just thinking out loud.

Chris

[trickjohn]

Hi - thanks for the ideas, the main 2.25 tube seems ok (fortunatly), the only one which appears to be rotten is the furthest o/s bracket, it was packed with dirt and mud and visualy looked alright until I removed the mud and had a good prod about with a screw driver. I have got a friend who is a good welder coming around later today - I want him to tell me if he could do the welding with a 3 to 4 inch partial lift - I am dreading having to do a complete body off as I only have a single garage and the body would have to be outside (under a water proof cover) until the chassis is repaired, but if this is my only choice then I will do it. I have christmas holidays coming up and this will keep me out of the pub and probably save me money.

Thanks for the reply knowing I can bounce ideas off people somehow gives me confidence I am doing the right thing.

[GreenV8S]

trickjohn said:

Hi - thanks for the ideas, the main 2.25 tube seems ok (fortunatly), the only one which appears to be rotten is the furthest o/s bracket, it was packed with dirt and mud and visualy looked alright until I removed the mud and had a good prod about with a screw driver. I have got a friend who is a good welder coming around later today - I want him to tell me if he could do the welding with a 3 to 4 inch partial lift - I am dreading having to do a complete body off as I only have a single garage and the body would have to be outside (under a water proof cover) until the chassis is repaired, but if this is my only choice then I will do it. I have christmas holidays coming up and this will keep me out of the pub and probably save me money.

Thanks for the reply knowing I can bounce ideas off people somehow gives me confidence I am doing the right thing.

I've not done it myself, but one technique that's been described for a body lift is to jack the whole car up a couple of feet, support the body and then lower the chassis. If you did that, you could separate them as far as necessary, maybe a lot more than 3-4 inches, but don't have to fully remove the body if you don't want to - it would remain above the chassis. That also sounds like a lot less work than fully removing it. Still a job that would probably be very difficult in the confined space of a single garage, but possible if you're determined I would think.

[Barkychoc]

My understanding is that to take the body off you need to jack the rear of the body up a couple of feet before moving the body rearwards.
I'm guessing that just jacking up the back end a couple of feet & not doing the rest would give you enough room - though I guess by the time you have got to this stage you're not far off removing the body.
I'd be tempted to go the whole hog, remove the body and check out that chassis bearing in mind what you've found on the bits you can see.
Why not take the body off outside - leave the body outside on some wooden joists covered with a waterproof cover - then wheel the chassis in your garage to work on it?

Chris

[baggiebird]

Hi Sean
I am not a welder or a bodywork expert. Clearly you have recognised that the geometry of the rear arm mounting brackets has to be exactly right, and seem to have some kit to help you achieve that. I have heard of a partial body lift using jacks and ply under the body, which may be enough. As Ray hints at though, it will be a very good idea to drain and make safe the fuel tank if working on these rear tubes. I was talking to someone from David Gerald TVR about S outriggers and he stated (I am not sure why) that if the rear outrigger tubes were gone (the ones that your brackets are welded to), that the chassis was not worth saving - I guess that is a reflection of the jigging difficulties? It sounds as if you can save yours though, so good luck and let us know how you are doing.

[mep12345]

I had to do the seat belt mounts and some of the outriggers and ended up moving to a full body off as I got more than I expected for when body was partially lifted. Have a look at www.gbsportscar.com what I found was pure . Having said that it wasn't until the body was fully off that the full extent was visible, particularly in the 2.5 inch area as you cannot get the leverage or force to fully check it out with the body in place (and it is still difficult even with a partial lift). However, a welder locally is doing the job and doesn't think repair is too difficult - quite expensive though.

Fortunately my suspension mounts are sound , but I feel for you as you realise when the body is off how susceptible these are to the dirt from the road.

Edited by mep12345 on Saturday 8th December 16:37

[trickjohn]

Hi all,

Thanks for the replies, that link above is one I had not seen, very helpful. I have been to the DIY shop this afternoon and brought thick ply and 4 x 3 wood. My friend the welder came round and under the car he went with a large hammer a few bangs and knocks (I was bricking myself for the verdict), solid was the remark and only surface rust, however he said that he could beef it up if I wanted by welding multiple lines then repeatly welding between them then grind back(he does old steam trains up as a hobby and he has demonstated good results before to me) . He thinks we will be alright with a partial lift and welding shields, petrol tank will need to be removed. If this fails or I find more rot then it will be body off. I would not fancy replacing the rear 2.25 dia tube but do believe it could be accurately, the body off process scares me more.
Therefore I will get the bonnet off tomorrow and get stuck in, car is already on axle stands and I am sure I will be constantly running between the car and the laptop for whats next.

Thanks again for the support and advise

[kenpage]

hi best of luck with this i also had rot in the mounts and decided on a body off rebuild, when off the full horrors were laid bare serious rot everywhere even in the large dia tubes the seat belt mounts looked reasonable but just twisted off even the rear shock abb towers were rotten so i took the chassis to tower view at cricklewood and asked if he could sort it out the reply was F*** me you must be joking so i have spent the last year trying to find another which i have just done and are now rebuilding. If you require swinging arm mounts tvr spares in devon told me they can laser cut new ones as they have the tvr jigs could be worth ringing them regards

[Barkychoc]

baggiebird said:

Hi Sean
I am not a welder or a bodywork expert. Clearly you have recognised that the geometry of the rear arm mounting brackets has to be exactly right, and seem to have some kit to help you achieve that. I have heard of a partial body lift using jacks and ply under the body, which may be enough. As Ray hints at though, it will be a very good idea to drain and make safe the fuel tank if working on these rear tubes. I was talking to someone from David Gerald TVR about S outriggers and he stated (I am not sure why) that if the rear outrigger tubes were gone (the ones that your brackets are welded to), that the chassis was not worth saving - I guess that is a reflection of the jigging difficulties? It sounds as if you can save yours though, so good luck and let us know how you are doing.

I also guess the chassis would not be worth saving to a dealer as they would have to factor in the labour cost, which you're providing free!

[Jed-S]

Sean,
Don't mess around with a body lift. Remove the body completely - it is the only way you'll get to see the extent of the corrosion and once it is removed it makes life so much easier to work on. It may sound a daunting task but a day spent unbolting everything (which you'll have to do most of anyway for a body lift) and 4 strong blokes and it was off. It is simple British engineering and the S follows the same philosophy of a kit car - a steel backbone chassis with a GRP body. If people can build a car in their garage then you can rebuild yours with your engineering background.

Expect something like The Little Shop of Horrors from http://www.gbsportscar.com site. That is actually worse than mine was and I knew I purchased a wreck. I feel for the people that are paying good money to have the front sections of the outriggers replaced and then they think that all is sorted. There is little or no mention of the rear sections and the horrors that await. By doing it yourself you'll know that it is all sorted and should last another 15 years.

Good luck.
Jed

[trickjohn]

Cheers Jed,

I know you are right (bugger, bugger, s**t and blast) - starting tomorrow - will read full body lift preparation again, it needs fixing - not repairing.

[mep12345]

Full body lift was about a days work to prep and about 8 people to lift off - much easier than I expected - don't be so daunted. My pictures actually look worse than they are for the 2.5" sections as they are sound inboard of the seatbelt mounts except on drivers side where 1 side of the trailing arm bracket needs work. What caught me out was the fact that the front sections which I believed had been replaced properly when buying the car were a very poor job, which was well hidden despite my best efforts to check. Dulford autos comment when asked about the work was "MMMM bit of a mess but I've seen worse!!!"

Reason why no-ones seen my site before today was I only built it today!!!!

Edited by mep12345 on Saturday 8th December 21:46

[Ray S]

Sean it's not as bad a job as you think,just take plenty of snaps as you do everything any problems you know where to find us ,quite a few of us have been through it you are doing the right thing you'll find a lot more when you get body off. Ray

[spludge]

I agree with Jed-S. I did a partial lift on mine just to clean up and paint the outriggers and rear chassis and very quickly came to wish that I'd taken the body off completely. With a partial lift you still have very resticted access which makes everything much more difficult and time consuming. Theres not that many more disconnects/removals you'll need to do to get it off completely anyway and you'll save a bunch of time on any chassis work that needs to be done.

If you decide to stick with a partial lift leave the suspension on untill you've done it as you may need to roll the chassis back to get the body high enough. Oh and make a careful note of where all the bits come from, the rubber pads for body mount for example may all be different thicknesses.

A suggestion about alignment if you have access to a lathe, it sounds like you might have:- Make up a spacer of correct length (clean up the inner faces of the brackets) from say 50mm dia bar, drill through and tap both ends and make up a matching pair of shoulder screws to engage in the brackets. If you use something like that you'll be able to remove it completely whilst cutting off the old bracket and be confident of getting the new one in the right place. You could probably use ordinary hex head setscrews (M12 or M14) to make the shoulder screws but watch the length on the inner one to make sure you can get it out before you weld anything!

K

[trickjohn]

Hi all,

I spent 6 hours on the car today. Outstanding tasks,
1) brakes not touched yet
2) I could not work out how to disconnect the large vacuum hose from the master cylinder does it just pull out - it is solid at other connection end and I did not want to force it.
3) Boot strut how do you get to undo it?
4) Remove hand brake lever.
5) Disconnect speedo and reversing light from gearbox.
6) Disconnect electrics from fuel pumps (is had in the boot?)

Thanks in advance for any help.

[clarenceboddiger]

If you get stuck for the brackets, I can probably get a couple bent up out of 3mm Steel, you would have to grind out the profile around the tube and drill the hole yourself though.

[GreenV8S]

Fuel pump electrics are accessed from under the car close to the back of the rear near side wheel arch. Vacuum pipe just pulls out of the servo but will need a lot of force plus some wriggling to release it.