Ralt RT30 clutch problems

[stobo]

Having problems with my newly acquired RT30:

(a) O rings - realise from other discussions that this is a recognised problem area, but surely they should last more that 2 outings. Any suggestions re supply of better qualiy o rings, other contribution factors, etc would be greatly appreciated. Previous owner had the car about 7 years and ran regularly, had the same problem for about the last 2 years (and sold the car to his unsuspecting offspring!);

(b) sourcing replacement parts - in particular clutch cylinder and thrust race. Will try local contacts, but there's not a big network of people here who know much about RT30's.

[Notso Swift]

Can I ask O rings for what?

Also name some of the required charaterisitcs and we may be able to help with suggested materials.

[phoenix]

Why not contact Ralt direct???

http://www.ralt.co.uk/

[TEAM78]

Im struggling myself on a Ralt that was made in May 1987, looking to get new brake discs for it. they appear to be road car discs that have been drilled and grooved. there not vented but are grooved. does anyone know what the discs are off?

[Tony C]

Not sure about the RT30 but the RT20 and RT21 used early SAAB clutch components, replace the standard rubber seals with viton seals and they should last a season, they did in the 20 and 21 F3000 cars.

[Notso Swift]

That is the sort info I was trying to get from him; regular seals are most likely made of Buna, Viton is more resistant to hydrocarbon based liquids (But if it is a shaped o-ring (D section or something) you may need the softer material to take up the space if you try and use a conventional BS o-ring
Now if he is using Silicon based brake fluid the problem changes again...

[TEAM78]

Originally Posted by phoenix

Why not contact Ralt direct???

http://www.ralt.co.uk/

I rang them and they didnt want to know as the car was too old. they werent even interested in offering any information on it.
typical british business sadly

[andy97]

Unfortunately the current owners of Ralt probably have absolutely no knowledge of the early cars as they were not associated with the company back in the RT30 days. They bought the company after March owned it; they might not even have any drawings for those cars. A shame but the fact is that whilst they share the same name they really are a completely different company to the one that built the car.

Best bet for advice is to try to find someone who runs a similar car. Ask on the Monoposto Forum (www.monoposto.co.uk) as there are several people there that have RT30s or similar era cars.

[Lola]

Advice i was given from Magic Motorsports is to use epdm. I did just that on my Reynard 883 and ran trouble free for 4 seasons. Changing them just once a year. I have found some advice they gave someone else on another website and here it is...

"Many people think that Viton is the material to use because it is the most expensive. Viton is not reistant to hydraulic fluid. The material to use is EPDM which is one of the cheaper synthetic rubbers but is, amongst other things designed to be resistant to hydraulic fluid.

Every Reynard manual we have come across has stressed this.

Take a look at

http://www.marcorubber.com/material_chart.htm

which will explain it all."

Sorry about the link moderator but im sure it will help.



Magic Motorsport - British Champions

[Tainan]

Have the same problem on my March F3. I've just changed from conventional o-rings to square-section ones, but it doesn't seem to have improved it much.

[stobo]

Apologies for not responding sooner. At the last change we put in o-rings (puurportedly) made of EDPM, based on similar advice to 'Lola' further down the link. Viton before that was not a great success in terms of durability, neither was whatever was used previously. I'm still hopeful that the EDPM o-rings have a bit more staying power and that I've just run into some other problem. As for the fulid I'm using a polyethylene-glycol fluid. Will get it apart this week to seee what other tales of woe are in there.

[stobo]

Originally Posted by andy97

Unfortunately the current owners of Ralt probably have absolutely no knowledge of the early cars as they were not associated with the company back in the RT30 days. They bought the company after March owned it; they might not even have any drawings for those cars. A shame but the fact is that whilst they share the same name they really are a completely different company to the one that built the car.

Best bet for advice is to try to find someone who runs a similar car. Ask on the Monoposto Forum (www.monoposto.co.uk) as there are several people there that have RT30s or similar era cars.

Thanks, will try that forum as well.