V8 front suspension

[Kevin H]

I thought some V8 owners might be interested in what's in those turrets on the front cross-member that the top of the suspension spring goes into. The components shown below deteriorate after a few years. The plastic and rubber parts simply disintegrate over time and the mild steel circular plate comes untreated from Bristol so you can probably imagine what happens to that.

When these parts are no longer present the front of the car will sit 1-2 inches lower and the stresses change for the worse where the front spring sits in the cross-member.

On my own 411 someone had simply 'solved' the problem by installing longer springs, which I discovered only when I added the missing parts and had a hellish job getting the springs back in. When we finally did it the front end sat too high. Needless to say I ended up getting new springs as well.

[Kevin H]

I just realised that you can actually see the components mentioned below, when they are there that is! (if they haven't previously been replaced they will have disintegrated in the last 30-40 years).

In the attached photo, at the top of the spring you can see all 3 parts, the rubber part that sits on top of the spring, the mild steel plate on top of that and you can just see the bottom of the spacer (yellow/orange in colour).

From what I can see on the parts list the steel "isolator" didn't exist on 408-410 and it has a 411 part number 411-1-23079 (assuming I am looking at the correct item on my invoice from Bristol Cars Services). It's obvious that this isolator would be of benefit to the older cars as well.

Look out for these when buying a V8 car up to and including the 411/412 - I don't know if they are used on any later cars. Cost of these 6 parts when I bought mine in 1999 was about £200 all up, so even accounting for inflation they're not very expensive to buy, although there's a bit of work involved in replacing them.

[Kevin H]

Another obvious thing to look out for when buying a V8 Bristol (up to and incl 411/412) is the front suspension failure shown below.

Basically the weld holding the shock absorber turret has rusted and given way and at the bottom end the shock absorber mounting has broken. I know it all looks horrific but it can be repaired reasonably easily by a competent welder.

The final photo below shows the top end repair. We ground away all the old weld, realigned the turret part which passes through the crossmember. We had a a solid steel ring manufactured to fit snugly over the turret and welded that to the crossmember and the turret with continuous seams all the way around.

The bottom shock absorber brackets are available from Bristol Cars Services.

Be aware that the car may still drive quite well despite this damage, so be sure to inspect the suspension.

[Kevin H]

As I collate all my Bristol archives I am still finding more front suspension things to be aware of.

The photos below show stress fractures in the spring seat pan. Unfortunately you can't see these unless the spring has been removed.

NB: As previously mentioned, someone had installed longer and probably stronger springs in my car (presumably to compensate for the missing distance piece on top of the original spring). We didn't realise this until we had reassembled the front suspension with the new distance pieces in place. This may have caused these stress fractures, but unfortunately I have no way of knowing.

The spring seat pans are available from Bristol Cars Services. They were £210 each when I bought mine in 2004.

[Kevin H]

Replacement of wishbone bushes
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The difficulty factor in this job really depends on how long the bushes have been in place. On my car we first tried using a 15 tonne hydraulic press to remove them. They wouldn't budge!

Some people attack them with a welding torch but this is dangerous due to the toxic fumes generated.

A method I found successful was to use a radial hole saw (example photo below) with a high torque drill to cut through the rubber section of the bush. A heavy duty cordless drill gave the best results, used at low speed (high torque), but I had to let the drill cool down occasionally. Do not attempt to use a drill which is not designed for high torque use - you will destroy the drill motor before you get the bushes out!

If you use a higher drill speed the rubber will melt, stick to your hole saw and possibly emit harmful fumes depending on just how hot it gets!

If doing both upper and lower wishbones, two different saw diameters will be required for the different diameter bushes. The hole saws need to have a minimum cutting depth of 24mm and you will need to cut from both sides. Outside diameter of the hole saw should be as close as possible to the inside diameter of the bush outer shell, so that the minimum amount of rubber is left inside the bush shell.

Once the rubber and centre steel cylinder have been removed from the bushes, you need to carefully saw through the outer steel shell of the bush. This can be achieved by threading the blade of a hacksaw through the bush before fitting the blade into the hacksaw frame. It is very difficult to saw to an even depth right through the length steel shell without damaging the wishbone. I made a cut into each side of the bush shell before 'peeling' each side of the shell inwards with a cold chisel to until the resistance was reduced to the point where the bush shell could be pushed out of the wishbone arm. Not surprisingly, the amount of corrosion between the bush outer shell and the wishbone arm correlates directly to how difficult it is to remove each bush.

When fitting the new bushes, with a hydraulic press, first coat the surfaces with some sort of anti seize product.

Note: When we discussed this on the BEEF mail list back in 2002, someone brought up the possibility of bushes having being replaced with items made from a modern synthetic rubber such as Viton, which is a fluoroelastomer. At the time we had no knowledge if bushes being made from Viton (although it is used in some automotive fuel applications), but care should be taken just in case. If a fluoroelastomer burns it emits hydrogen fluoride gas, which on contact to water turns immediately into hydrofluoric acid, which is very very dangerous stuff!

If you drill at low speed with a sharp hole saw and don't allow the material to get too hot you should be okay regardless of what the bush is made from. There was also a suggestion that the bushes could be frozen first.

The usual disclaimers apply