Oil leak by rear wheel - damper?
Oil leak by rear wheel - damper?
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braddo

Original Poster:

12,001 posts

208 months

Tuesday 14th April 2020
quotequote all
I noticed there was a damp patch by my Caterham even during this lovely weather. It was just in front of the driver's side rear wheel and it turns out that it is oil - clear, clean-smelling oil. There is nothing other than the diff (which is dry) or a damper that it could be, right?

I think the damper has spewed oil over the fuel pump and lines and it has dripped down to the ground from there. Any views from more experienced folk gratefully received!

A few photos after I removed the right rear wheel:








It's a '96 Caterham and I'm guessing those dampers and springs are original!


Eugene7

741 posts

214 months

Tuesday 14th April 2020
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Difficult to tell, but that looks like the diff?
Do you have other images?

HustleRussell

25,951 posts

180 months

Tuesday 14th April 2020
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Oil on damper body and in the damper well would suggest damper to me as you suspect OP.

F355GTS

3,820 posts

275 months

Tuesday 14th April 2020
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Diff breather?

BertBert

20,675 posts

231 months

Tuesday 14th April 2020
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Looks like too much oil to come out of a damper to me.
ETA, but if they are original 1996 dampers, get them changed for new pronto!
Bert

braddo

Original Poster:

12,001 posts

208 months

Tuesday 14th April 2020
quotequote all
Here are a couple of photos of the diff, from the left and right showing a dry casing.

Sounds like I need to locate the diff breather hose and check where it leads?

From the left looking forwards:


From the right:


braddo

Original Poster:

12,001 posts

208 months

Tuesday 14th April 2020
quotequote all
BertBert said:
but if they are original 1996 dampers, get them changed for new pronto!
Bert
That's gonna be my next question! biggrin What dampers?

I like the soft road-biased setup even though I do a few track days, because it opens up a whole lot of little fun roads that can't be enjoyed in a stiff car. And I like the way it can float over road imperfections that you have to brace yourself against in a GT3 etc.

Having adjustable platforms would be good though. Basic Nitrons from Meteor Motorsport look like compelling value against the factory Bilstein options but t'internet suggests Bilsteins have a longevity advantage?

SimonRogers

146 posts

178 months

Wednesday 15th April 2020
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Try me - May be able to sort some street series out for you.

BertBert

20,675 posts

231 months

Wednesday 15th April 2020
quotequote all
braddo said:
That's gonna be my next question! biggrin What dampers?

I like the soft road-biased setup even though I do a few track days, because it opens up a whole lot of little fun roads that can't be enjoyed in a stiff car. And I like the way it can float over road imperfections that you have to brace yourself against in a GT3 etc.

Having adjustable platforms would be good though. Basic Nitrons from Meteor Motorsport look like compelling value against the factory Bilstein options but t'internet suggests Bilsteins have a longevity advantage?
I think you have lots of choice for dampers. I'm always a big fan of factory standard as I have seen soooo many DIY suspension cockups! But Simon knows his stuff, so he'll sort you out if you want different choices.
Bert

braddo

Original Poster:

12,001 posts

208 months

Friday 17th April 2020
quotequote all
SimonRogers said:
Try me - May be able to sort some street series out for you.
Cheers - think I'll give you a bell next week.

braddo

Original Poster:

12,001 posts

208 months

Sunday 19th April 2020
quotequote all
I located the diff breather, which is an open tube about 3 inches long from the top of the diff. There is evidence of it spitting stuff out but nothing recent or runny.
As per original post the oil on the ground has been clear and clean; my past experience of diff oil is that it quickly gets a ‘used’ smell? Right??

Anyway, they are signs of leakage on both rear dampers.

HustleRussell

25,951 posts

180 months

Sunday 19th April 2020
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EP gear oil reeks

BertBert

20,675 posts

231 months

Monday 20th April 2020
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Best bet is to fit new dampers (and springs?), Clean up the oil and see what happens.
Bert

mickrick

3,745 posts

193 months

Monday 20th April 2020
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Clean it all off, spotless, and spray some dry cleaning powder (the stuff in an aerosol that they use in the restaurant when you spill your soup down your tie wink )around the top of the damper where the rod exits. If it's coming from the damper the only place it can come from is the rod seal. The white powder will turn dark in the area of a leak.

braddo

Original Poster:

12,001 posts

208 months

Monday 27th April 2020
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Update - I decided I would definitely replace the rear dampers and springs. After a few discussions and lots of ruminating I have ordered straight replacements (fixed bilsteins from Caterham). I had to remind myself why I bought the car, which was to enjoy back-to-basics low-cost motoring, and that I like the current setup. I don't want to change the car or dive into the time/money of corner weighting and geo tweaks etc.

So I'll have a go at changing the dampers but there will probably be seized fittings that will make my attempt short-lived! I will be interesting to feel the difference going from old to new versions of the same product. And I'll look into getting the fronts rebuilt by Bilstein.

HustleRussell

25,951 posts

180 months

Monday 27th April 2020
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From memory there may be a reduced head bolt involved when removing the rear dampers which is easy to round off and is best attacked with a ground down socket. I think it holds the roll bar on?

Tango7

692 posts

246 months

Monday 27th April 2020
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HustleRussell said:
From memory there may be a reduced head bolt involved when removing the rear dampers which is easy to round off and is best attacked with a ground down socket. I think it holds the roll bar on?
There is reduced head socket which does hold the rollbar down but it doesn't need to be touched if you are just removing the shock absorber. The top bolt is accessed from behind the passenger seat and might be covered by bulkhead carpet and/or a small alloy panel riveted into place. The bottom bolt is a 19mm one. Don't forget to jack your car up and rest the chassis on axle stands to allow the de dion tube to be unsupported to make removal of the suspension unit easier.

Aeroscreens

458 posts

246 months

Tuesday 28th April 2020
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Tango7 said:
The top bolt is accessed from behind the passenger seat and might be covered by bulkhead carpet and/or a small alloy panel riveted into place.
On earlier cars, certainly my '93 chassis, the top bolt of the damper is accessed behind the large rubber grommet on the ali damper panel in the boot.

braddo

Original Poster:

12,001 posts

208 months

Tuesday 28th April 2020
quotequote all
Tango7 said:
The top bolt is accessed from behind the passenger seat and might be covered by bulkhead carpet
This is what mine is and is a hex / allen key type bolt.

Does anyone know if the other end of the bolt needs a spanner on it to stop it spinning?

BertBert

20,675 posts

231 months

Tuesday 28th April 2020
quotequote all
braddo said:
This is what mine is and is a hex / allen key type bolt.

Does anyone know if the other end of the bolt needs a spanner on it to stop it spinning?
Almost certain it is a captive nut.
Bert