how to tell what whisbone I have

[kenneth.mula]

Hello

I have an 1987 caterham with (I think) a swapped frame. I think It is an imperial one because; "lower horizontal chassis tube in the rear wheel arch, the one that the rear ARB is bolted to. If it's round for the full length, it's imperial"

 

I am having trouble getting the damper bolt off my lower wishbone at the front wheels. And think I have to get a new set. I think I have a widetrack front.

Is there a way to measure what I have, and find the right one to order?

I have Ohlins dampers with springs that is 64N/mm (365Pounds/inch).. and I need to get new softer springs

 

Hope some of you know how I can find the correct one to buy

 

:)

[ECR]

As you've got the wishbone off the car you're reasonably mechanically competent so you may well have tried the following.

Soak the threaded part of the wishbone (the end opposite the headed end of the allen screw) with Plus Gas for a few days (WD40 is no good for this). Alternatively (or as well) immerse that part of the wishbone in a parrafin bath and leave for a few days. At that point get some heat onto the area and try undoing with a 5/32 (corrected to 7/32") a/f allen socket (they are much more effective than a normal "L" shaped allen key). If you still have difficulty, try undoing with an impact driver (using the same socket)

Only then consider buying a new wishbone

 

Good luck

[rj]

A 4mm allen key is marginally bigger and would probably go in - if not wack it in to have the best fit possible.

[aerobod - near CYYC]

I would be surprised if the imperial wishbone allen bolt socket is as small as 5/32", the metric one is 6mm, with 7/32" or 1/4" being closer sizes, especially if the bolt thread is 5/16", matched by the metric M8 one.

[thompster]

Easiest way to tell a metric chassis from imperial is the diagonal braces in the engine bay. The imperial chassis has long diagonal braces about 1m long from the centre in front of the scuttle towards the front of the car. The metric chassis has short diagonal braces just in front of the footwells..

Definitely try the plus gas / impact driver first.  Even cutting the bolt off with something like a Dremel speed-clic disc would be better than a new wishbone.  Nice shocks btw.. let me know if you want to swap :-)

[Richard Price]

Imperial wishbones definitely use 5/16 UNF cap head bolts that require a 7/32 key.

[kenneth.mula]

Hello again

Thanks you all for the help. I will try the pluss gas (or something equivalent). I guess I have an imperial chassis then because the allen key has an 7/32 head. I live in Norway and had to get one to try. 

I have a hydraulic handbrake on the car, and Have been trying to find the place where the original handbrake is to be mounted. Is there a "race" chassis without this? I haven't been able to find where I should mount a handbrake lever.

Today I have an hydraulic one, and I don´t think I am going to go "rallying" anytime soon and would prefer a "normal" handbrake.

The dampers are ohlins, but I have talked to SImon at meteor sport and he tels me that the dampers are to short, and the springs are to hard. When I put my foot down, and wheels spinns the car starts to "jump" I won´t do doughnuts, but I don´t like the "jumping" of my rear wheels.

Am thinking of swapping the ohlins to the tractive 3 way dampers. Anybody tried these?

Here is a picture of the engine bay, and if I am correct the car is imperial. Had a gearbox service and removed the engine. :)

[SLR No.77]

If your car is 1987 (as stated in your first post) it's DEFINITELY Imperial. The metric chassis wasn't introduced for another 15 years.

Stu.

[Richard Price]

 

"I have an 1987 caterham with (I think) a swapped frame"

 The front damper mounts look like they don't share the top wishbone mounts, so it looks like it has post 96 geometry.

[SLR No.77]

 The front damper mounts look like they don't share the top wishbone mounts, so it looks like it has post 96 geometry.

And the pedal  box looks like it's an Imperial chassis as well.

[ECR]

Apologies, working from memory in a foreign country

Quite right, its 7/32"

[Sim]

Plus gas for a few days, then impact driver

 

Simon

[Bricol]

And then when you round it off, bash in a torx drive - they often succeed as the fit is more  . . . acgricultural and doesn't slip.  Plus the vibration from hammering it in assisting in breaking the rust grip.

 

[kenneth.mula]

Hello all

Got a 7/32 ( plus some other imperial tools) from the local shop. The other side did come of :)

The stuck one had the allen bolt broken (cracked). Tried to veld another bolt onto this one. But the allen bolt broke of.

Then there was only one thing to do, cut the damper off with an angle grinder. After a little while the damper was loose at last. "hurray!!!"

Now the next question is what to do with my damper/spring setup. I have to stiff springs, so these have to be swapped to more appropriate ones. 

My front damper is to short so I need to have them serviced. Or I can swap these for a set of tractive 3 way dampers with the right springs. 

Have tried to google any caterham/tractive comination, but have not  found anything yet.

Guess they are much better than my seup, but still the price is nearly the double.

Anyway.. thanks for your help so far :)