Slave & Master Clutch Cylinders New or Rebuilt

JBC · JBC's Garage

I have to replace my slave and master clutch cylinders. The line between the two seems fine and looks good. The line from the reservoir to the master could use a replacement. Rebuild or new? Thoughts?

Looks like ~$155 for new (both units) and about half or slightly less that for rebuild kits.

JBC · JBC's Garage

Quote:

Originally Posted by JBC

I have to replace my slave and master clutch cylinders. The line between the two seems fine and looks good. The line from the reservoir to the master could use a replacement. Rebuild or new? Thoughts?

Looks like ~$155 for new (both units) and about half or slightly less that for rebuild kits.

Sorry, just did a search and there are many threads on this one. Should have done that first.

flash968 · 10-04-2014, 05:50 AM

i spent 25 years dealing with bad hydraulics on british cars. the problem with rebuilding them is that it is entirely dependent on the condition of the cylinder casting, which you won't know until you put it back together. you could easily go through all the trouble and effort, and have it fail again.

it didn't take long before i learned that it was cheaper to buy new than to do the job twice. the tow truck alone cost more than the parts.

ernie9944 · ernie9944's Garage

Hate to agree with flash

but +1 ,save yourself a lot of problems & buy a new one.

pfarah · pfarah's Garage

And don't forget to replace the blue line between the brake reservoir and clutch master cylinder...

JBC · JBC's Garage

Quote:

Originally Posted by flash968

i spent 25 years dealing with bad hydraulics on british cars. the problem with rebuilding them is that it is entirely dependent on the condition of the cylinder casting, which you won't know until you put it back together. you could easily go through all the trouble and effort, and have it fail again.

it didn't take long before i learned that it was cheaper to buy new than to do the job twice. the tow truck alone cost more than the parts.

I just pulled the slave off and looked at it closely. I came to the same conclusion as Flash without reading his post. I was coming in to see what is included in a rebuild kit first but I was concerned about the casting also and thought it a 50/50 proposition for success. I need to think about it and tear down the current cylinder and make a decision.

flash968 · 10-04-2014, 07:59 AM

yup - i hate doing stuff twice, and i especially hate dealing with brake fluid. my time is worth more than the difference in parts cost, and then there is the cost of the tow truck (if you don't have AAA) and just the hassle factor of dealing with it. the last time i had the 968 towed, a ramp board the driver was using flipped up, smashed a headlight, and dented a fender.

another part to change would be the high pressure line. at least on the 968, it is well known for blowing at the coupling, and frequently does it right after putting in nice new strong components. the pressure finds the remaining old weak part, and then you get to go back in there again.

JBC · JBC's Garage

Quote:

Originally Posted by flash968

yup - i hate doing stuff twice, and i especially hate dealing with brake fluid. my time is worth more than the difference in parts cost, and then there is the cost of the tow truck (if you don't have AAA) and just the hassle factor of dealing with it. the last time i had the 968 towed, a ramp board the driver was using flipped up, smashed a headlight, and dented a fender.

another part to change would be the high pressure line. at least on the 968, it is well known for blowing at the coupling, and frequently does it right after putting in nice new strong components. the pressure finds the remaining old weak part, and then you get to go back in there again.

Outstanding point on the weak spot. I will replace the line. The internals of both the slave and master a smooth and clean. I'm tempted to rework due to the condition of the inside.

flash968 · 10-04-2014, 04:12 PM

it has been successfully done. having had it fail before, i'm just not inclined to roll the dice anymore. the parts are too cheap, and my time is worth more than the difference in price.

and then there's that whole "tow" thing if you guess wrong. by the way, this was exactly how i got the busted headlight and dented fender. i guessed wrong, the clutch hydraulics blew, and i was stranded on a windy canyon road. lucky i didn't get killed.

JonA · 10-05-2014, 12:31 PM

I couldn't find a rebuild kit for the master cylinder. Anyone have a source? I saved the cylinder that I took out as the bore was good and I would rebuild it and use it as a spare if a kit was available.

Jon

Bradical · 10-05-2014, 12:59 PM

When I was bleeding out the old nasty brake fluid when I got my current NA, the slave cylinder literally blew apart. So, I ordered a new one, and while I was bleeding it the master cylinder blew apart. So, I ordered that and the high pressure line, and the motive power bleeder. As soon as I pressurized the motive to 3psi the blue hose exploded and sprayed brake fluid everywhere. Now, whenever I start a job on this car, I buy everything that's within 10 inches of what I am working on...

Gawernator · Gawernator's Garage

Quote:

Originally Posted by Bradical

When I was bleeding out the old nasty brake fluid when I got my current NA, the slave cylinder literally blew apart. So, I ordered a new one, and while I was bleeding it the master cylinder blew apart. So, I ordered that and the high pressure line, and the motive power bleeder. As soon as I pressurized the motive to 3psi the blue hose exploded and sprayed brake fluid everywhere. Now, whenever I start a job on this car, I buy everything that's within 10 inches of what I am working on...

Lmao, that's pretty funny. It's true with older 944's for sure. There's a couple parts I wish I had bought earlier, because you'll find yourself doing the same job multiple times, instead of just buying all the parts and doing it 'while you are in there".

flash968 · 10-06-2014, 04:56 PM

yup - over in the 968 group, we've had hundreds of the high pressure lines go. some people would change only that line, only to find that either the slave or master blew shortly thereafter.

hydraulics are no joke. that pressure is huge. degradation and failure originates on the inside too, so you can't inspect it visually. further, the seals and hoses are only rated for 8 years. yes, most of them live longer than that, but many don't, and often because the system was not flushed every 3 years, as it was supposed to be.

i think it's penny wise and pound foolish to mickey mouse around with this one. it's just not that expensive to do it right the first time.