Brake Master Cylinder Refurb

[DCrompton940]

I have a problem with the brake master cylinder on a 1994 940 (with ABS), it seems as if the seals need replacement. My plan was to refurbish the unit with new seals, the kits are available. The Haynes manual says the a refurb on post 1992 models or models fitted with ABS is not possible.

Has anyone done a refurb of the master cylinder on a post 1992 model or one with ABS, by refurb I mean hone the cylinder and replace the seals? Perhaps someone knows why its not possible where an ABS is fitted.

[Rumbo]

Originally Posted by DCrompton940

I have a problem with the brake master cylinder on a 1994 940 (with ABS), it seems as if the seals need replacement. My plan was to refurbish the unit with new seals, the kits are available. The Haynes manual says the a refurb on post 1992 models or models fitted with ABS is not possible.

Has anyone done a refurb of the master cylinder on a post 1992 model or one with ABS, by refurb I mean hone the cylinder and replace the seals? Perhaps someone knows why its not possible where an ABS is fitted.

I'd be interested in this,mine is acting up,apparently it's the return spring,having to pull the clutch pedal up every two or three changes...

[DCrompton940]

The manual says that the clutch master cylinder can be refurbished with new seals etc.

[Rumbo]

Originally Posted by DCrompton940

The manual says that the clutch master cylinder can be refurbished with new seals etc.

I've been looking around at the service kits and all they seem to include is the seals,not seen the spring...

[Laird Scooby]

When was the Haynes Manual you're referring to originally printed? I've come across things like this before where Haynes (or another publisher) has stated a certain task isn't possible but often without giving the reason why.

Usually the reason is the manual was printed in say 1997 and covers the model up to 96 but the manufacturer is saying at that point there are no service kits for Item X and as such Item X must be renewed complete.

This is just a wild guess based on a few things i've found over the years, might be wrong or i might be right.

My line of thought is if the service kit is available then it should be possible to repair/rebuild it anyway.

[Alasdair1]

I've come across this in Haynes manuals as well. Normally with gearboxes etc. It should be possible as most sold are probably refurbished. I put it down to Haynes assuming it is to tricky for even an experienced DIY mechanic and perhaps covering themselves by suggesting it be taken to a specialist or replacing with new. I was going to do mine on an old 91 940 but got one from Brakes international for around £60-00. When I added the kit price and my time I reckon it was cheaper and easier to get a new one. I have used them quite a few times for brake calipers etc and have been very happy with the service. They sometimes ask for the original to be returned and a deposit refunded. Its always a problem as my post code is IV3 which is normally classed as not mainland uk although we are!

Alasdair

Alasdair

[DCrompton940]

The manual I have was printed in 2007 so its not a case of an early print. On the whole its not an impressive manual with very scant detail on many aspects of the car. In general, quite a few notes without explanation. I will take if off tomorrow and do some 'on the bench' investigation, the results of which I will post here with photos if necessary

[Laird Scooby]

Sometimes they don't always update things when service kits become available - just saying! It's possible yours is a reprint in 2007 from an original in say 1998 or something before the seal kit was available.

Getting it off and having a good look sounds like a plan, what makes you think the master cylinder is faulty though?

[Joe of Loath]

Originally Posted by Alasdair1

I've come across this in Haynes manuals as well. Normally with gearboxes etc. It should be possible as most sold are probably refurbished. I put it down to Haynes assuming it is to tricky for even an experienced DIY mechanic and perhaps covering themselves by suggesting it be taken to a specialist or replacing with new. I was going to do mine on an old 91 940 but got one from Brakes international for around £60-00. When I added the kit price and my time I reckon it was cheaper and easier to get a new one. I have used them quite a few times for brake calipers etc and have been very happy with the service. They sometimes ask for the original to be returned and a deposit refunded. Its always a problem as my post code is IV3 which is normally classed as not mainland uk although we are!

Alasdair

Alasdair

Haynes' difficulty ratings are almost completely arbitrary. According to them, replacing the entire steering rack on my Skoda (which involves dropping the front subframe) is the same difficulty level as changing just the tie rod ends!

[DCrompton940]

Thanks Laird, not going to reply on Haynes. I have redone the brakes back and front, bled, all working, no leaks but pedal still a bit spongy. The MC also makes a groaning noise when you push the pedal, something you can't hear when driving