Clutch Issues

[Ben Baxter]

Right, my Herald hates going to shows in the rain.

Got in today with all intentions of driving over to Cranleigh and the clutch pedal went straight to the floor. Seems to have leaked clutch fluid over the road (hard to tell as it's been raining all morning!). Put new fluid in and pumped the pedal to build up some pressure and biting point now appears to be about one inch from the carpet.

At a guess would that be the seals on the master/slave cylinders or something more serious?

[Ben Baxter]

Is it a big job to get the cylinders out and/or change the seals?

Speaking to a novice who is more than willing to try his hand here, just like to know what I'm getting myself into thats all!

[sallyann]

Probably easier to fit a new slave cylinder but if you have new seals go for it ,its easy to do!

[heraldcoupe]

If you're changing seals, do the master and slave simultaneously. That way you can properly clean out the system so there is no cross contamination to the new seals.
There are two different slave cylinders depending on clutch type - coil or diaphragm sprung. The same master cylinder was used throughout,
Cheers,
Bill.

[Ben Baxter]

Was thinking I might as well do that anyway while I'm in there. Any thoughts on how long it'd take me? Couple of hours?

[heraldcoupe]

Biggest hassle may be dismantling the master cylinder, they often won't give up the piston without a fight. Give yourself a head start by cleaning the end of the bore and circlip groove properly before trying to get it out. Use some fresh brake fluid to lubricate the path of the piston.
Two hours is reasonable, but allow more in case of difficulties like this.
Cheers,
Bill.

[rotoflex]

I again vote for just getting replacement master &/or slave cylinders.

Replace them, put the originals in a box for next time.

Next time, rebuild the originals & swap them on the car.  You'll already have experience for the removal & installation half of the job, & each job will be easier the first time with just one part to do.  Make it easier on yourself, the first time on a particular job you need more time, have more problems to solve, etc.

[Clive]

And its a pain if you buy the seal kit, spend the time pulling it out and then finding the cylinder bore is shagged. But the seal kits are cheap, the cylinders not so.....

Get the seal kits and try if no hurry..... Buy new cylinders if you have to.

BTW tricky old job from underneath the car. A doddle from inside, but you have to take the gearbox tunnel out, can be easy if in good nick, but many have been hacked about. While you are there check gearbox oil etc etc.

[Ben Baxter]

Had a look today in my lunchbreak (ah, the joys of living next to work), looks like it's the slave that's gone, seals ordered as I'm a) skint and b) have the time anyway. I think the master cylinder isn't that old anyway, sure I've a receipt for a clutch overhaul at some point in the 90's (and the cylinder is pretty shiny with a nice clean cap - the car has only done about 5000 miles since 1989), whereas I think the master brake cylinder is original. Like advised I'm going to do both at the same time, and top up the gearbox oil.

In no hurry, got a couple of days to play with and a month off coming up too.

The gearbox tunnel is in good nick (see picture), will be no problem to get off at all I think, had all the carpets out last month so know where I'm going with that one, and means I get to admire the floorpans again.

Had some varied advice for what brake and clutch fluid to put in, anyone got any definitive answers for me?

[Clive]

New stuff! honestly I don't think it will make any difference which DOT you use. especially in a clutch where heat is no problem.

[Ben Baxter]

Changed all of the seals, took about an hour and a half all told, hardest bit was getting the diapraghm seal on the slave cylinder to stay put, that and finding the small yellow piece of plastic from the master cylinder that shot off across the kitchen when I undid the spring.

Getting a new bracket to attach the slave to the gearbox with, as although both the cylinders look in good nick with no wear to the bores etc I don't like the look of the bracket, looks as if it's been clouted with something as it's not sitting flush to the gearbox on one edge.

Biting point is decent now, though appears to be about an inch closer ot the carpet however, is that just because I have decent pressure in the system and new seals? Not bad to drive with, just will take a bit of getting used to when pulling away and reversing.

Its the problem with never having driven another herald, when I've replaced or fixed parts I'm not sure if a the performance/handling changes are down to a miscalculation I've made or just due to having non-buggered parts!

[Beans]

If you're using OS seals in the cilinder use DOT3 otherwise DOT4. The latter seems to be more agressive and old seals perish rather quickly as a result. If you are using new seals (read modern) DOT4 shouldn't be a problem
Don't use DOT5 (silicon) in the clutch. I wouldn't use it in the brakes either

[Ben Baxter]

Don't think I could bring myself to trust 38 year old rubber, surely it wouldn't survive very well unless actually kept in some kind of fluid to prevent it drying out?

Used DOT4, seems about right.