Anyone else experience pre-mature failure w/DMC master clutch cylinder...ugh

[Jeffu]

I purchased a DMC "improved" master clutch cylinder back in May 2010. At the same time I also purchased the SS braided clutch line. The reason for the replacement was due to the old Girling unit leaking. The mc and braided line installation went fine. In hindsight I probably should have replace the slave but didn't (plan on doing that now though). The entire system was bled and filled with new fluid and it was working perfectly or so I though.

Just the other day I noticed my new mc beginning to to show signs of leaking around the front boot. What really makes me upset is now I have some drips of fluid on my brand new floor mats! If I let it go much longer it will end up on my new carpet as well! It's very frustrating because I literally have less than 1,800 miles on it.

Since it is "nearly" two years since my purchase it is not covered under any kind of warranty. Anyone else run into similar issues??? I have considered just rebuilding it because the thought of shelling out another $100 bones doesn't make me all that excited!

I have read on this forum site about this rebuild kit: "Autozone Part # 22320 $21.99 Cross Reference Vehicle: 1981 AMC Spirit 4.2L 2BL 6cyl." My only question is this must be a rebuild kit for the old Girling unit and I am unsure if it would work for the new DMC improved unit? If any one has some insight or similar experience I would like to hear from you.
Thanks!

[r00b]

I had bought one and installed it a few months later. Not long after it started leaking, 90 days was up so I ended up using an old master cylinder.

[ccurzio]

I talked to John Hervey two weeks ago about clutch cylinders and he was just telling me that he's been seeing a really high degree of exactly this kind of premature failure in DMC's clutch cylinders. He has no idea why it's happening but expressed the (understandable) disappointment that since the originals can in most cases last 30+ years, why can't a new one last for less than even half that.

Of course he also sells clutch cylinders for the DeLorean and he insists they're far superior, so he's got a business interest in talking shit about the competition. At the same time, I don't know how many times people have had problems with his cylinders AND I just saw this thread was posted only a few days AFTER Hervey off-handedly mentioned to me that he was seeing abnormally high rates of too-early DMC clutch cylinder failures. So take that as you will.

Believe me, I'm not at all happy to see this trend. Just a few months ago the stock slave cylinder in my car shit itself and I replaced it with DMC's new part. I don't like my chances.

[Michael]

Anyone else experience pre-mature failure...
Try thinking about auto transmissions when you shift.

[DMCMW Dave]

That's pretty wierd as we've installed dozens, maybe hundreds, of clutch masters in the past 5+ years and have not seen or heard of any failures, not even over the counter sales returns. I'm sure the other shops are selling them at the same rate. I don't even recall any out-of-box failures in the shop. I don't think we have ever replaced a clutch master in a car that was not an original (we would notice!).

What kind of brake fluid are people using that are having such problems?

I have not exactly seen a lot of people mention it here, and generally this community is pretty quick to bitch about a problem like this. I can't say they will never fail, just that I don't see an epidemic here.

FYI - I've yet to see a defective/failed repro slave either.

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I wonder what "a high degree" is. There is different part in particular where the (non-DMC) vendor claims he's never had a return, but we've had to replace almost every one that comes in here on a car (due to failure). It is a total of maybe 5 units out (of 6 that we have seen) so I can't really say it's a "high degree" as there may be hundreds out there working fine that I don't see. Statements from competitive vendors have to be taken with a grain of salt. The hundreds of customers with non-failed parts are not calling him, and it goes both ways I'm sure.

[David T]

Very hard to draw conclusions off of the experiences of just a couple of owners. Too many variables including mechanical abilities, type of brake fluid, how the part was handled, etc. The M/C does not appear to be a part with a high failure rate unless you have old, sludgy brake fluid. You should contact the vender and see if they will give you any discount on a replacement. Most of the time they will bend their own rules to make a customer happy. I am sure they would be curious to know why it failed and if it is any kind of trend.
David Teitelbaum

[amuderick]

I purchased my car from DMCFL a year ago. They replaced the clutch master before the purchase. The other week I noticed the telltale drip coming down from the clutch onto the floormat. The car has had about 1000 miles since the replacement.

Definitely a bummer.

I will probably contact them next week to let them know. But I saw this thread and figured I'd put in my $0.02.

[Chris Burns]

I purchased my car from DMCFL a year ago. They replaced the clutch master before the purchase. The other week I noticed the telltale drip coming down from the clutch onto the floormat. The car has had about 1000 miles since the replacement.

Definitely a bummer.

I will probably contact them next week to let them know. But I saw this thread and figured I'd put in my $0.02.

Sounds like your Clutch Master Cylinder is going bad.

[DMC5180]

This Early 2000's DMCH Reproduction Clutch Master was Installed at DAVE's House Before he started DMCMW. It shows slight signs of fluid residue (no liquid drips)
I deem this to be normal signs of use. A liquid stream would only indicate a worn piston O-ring. Not necessarily a failure of the cylinder cup seal. (which would be a true failure of the unit)

9626

I've had a true cup seal failure happen on an old Audi I had. I had to drive the car 4 days with no clutch. (waiting for Parts) It made negotiating starts and stops interesting. It had a really low 1st gear which was easy to start the car in gear when ever I had to fully stop. No clutch shifting was really easy in that car.

[dmc6960]

I installed a new master and slave in late summer or early fall of 2010. No problems yet.

[stevedmc]

Last year (July 26th to be exact) I transferred the guts from a 1981 AMC Spirit clutch master cylinder to my Delorean clutch master cylinder and have been driving since then without a single leak. My 30 year old clutch master cylinder seemed to be working fine at the time but I swapped the guts out simply because I don't trust 30 year old rubber seals.

[Chris 16409]

Last year (July 26th to be exact) I transferred the guts from a 1981 AMC Spirit clutch master cylinder to my Delorean clutch master cylinder and have been driving since then without a single leak. My 30 year old clutch master cylinder seemed to be working fine at the time but I swapped the guts out simply because I don't trust 30 year old rubber seals.

Steve do you know if the whole AMC part will work. I know they have integrated fluid bottles, but has anybody just tired to see if it fits?

[1batt4u]

I remember Martin DMCUK posted a link for a good quality performance master cylinder clutch. I tried looking for it on the forum, but nothing. Maybe someone remembers and can find it and post it?

[Chris 16409]

Here is a picture of the threaded hole with the mating surface. It looks really jagged to me. I was getting fluid leakage from the threads.

[stevedmc]

Steve do you know if the whole AMC part will work. I know they have integrated fluid bottles, but has anybody just tired to see if it fits?

It all depends on whether or not the AMC part has an integrated fluid bottle. It is getting harder and harder to find AMC clutch master cylinders with the bottle separate from the part. If the fluid bottle is integrated, it will not fit (unless you get fancy and figure out a way to relocate it). If the fluid bottle is separate, it will fit.

You can get a rebuild kit for about $15 from AutoZone but the rebuild kit does not come with a warranty.

For a few dollars more, you can purchase the entire assembly (with the integrated bottle unfortunately) and transfer the guts from the new part to your old one. This may sound ridiculous, but if you purchase the entire assembly you get a lifetime warranty and will never need to purchase another rebuild kit again as long as you keep the old housing. In 10 or 15 years when your clutch master cylinder starts to leak again, transfer the bad parts to the new housing, throw some dirt on the housing, and walk into AutoZone (or whoever end up buying them out) and get a new master cylinder with new guts for another rebuild.

[stevedmc]

On another note, if your master cylinder is pitted, you will need to replace it. If it needs to be replaced, just call up your vendor of choice. I like DMCMW.

[stevedmc]

Bill Robertson buys his clutch masters new off eBay:

http://sphotos-b.xx.fbcdn.net/hphotos-snc7/402645_455028347875754_990671097_n.jpg

They have the exact same Girling numbers cast into the side, so they are a 100% perfect fit (you have to swap the pedal pushrod over of course).

[stevedmc]

Steve do you know if the whole AMC part will work. I know they have integrated fluid bottles, but has anybody just tired to see if it fits?

Only the 6 cylinders have integrated reservoirs. 4 cylinders have remote reservoirs (picture of a 1981 4 cylinder AMC Spirit's clutch master in its native environment):

http://sphotos-b.xx.fbcdn.net/hphotos-ash3/579740_455105727868016_1965607530_n.jpg

[ramblinmike]

The guts-transfer method does work. I've been running it for 6+ years after my first replacement (not from DMCH) failed.

I used a wheel cylinder hone to clean up the bore and it works perfectly. I did swap the spring from the failed unit after the replacement felt funny. I haven't check for leaks, but the fluid was all the way up when I checked earlier this summer. Works great.

[David T]

I just did a clutch master, slave and hose for a local owner. It bled easily and seemed to work OK till I tried to test drive it. If you held the clutch pedal down in gear it started to engage like you were letting up in the clutch pedal. I tried rebleeding it several times and it did not help. Finally I figured something was wrong with the master cylinder so I took it out and took it apart. Refer to E:07:01 bottom of the page. The seal all the way to the right was missing. I called the vendor and he immediately recognized the problem and said he would send me out a seal. In the meantime I recycled the one from the old master cylinder. That seal blocks off the reservoir so the fluid can't escape and release the clutch while you are holding the pedal down. This was a rebuilt so it is probably just a case of the person rebuilding the cylinder messing up. As for how stock ages compared to parts in use, things age differently. Parts that were assembled 30 years ago and put into stock were not preserved to be on the shelf for that long a time. The seals can go bad just because they have not been moved for so long. The assembly lube can deteriorate and affect the rubber. IMHO you cannot take a part like a clutch master cylinder with rubber seals in it, leave it in a bin for 30 years and then expect it to not leak if you put it into service. NOS is just that, New OLD Stock. And by now it's 30 years OLD! That is not to say it's worthless, you have to disassemble it, inspect the parts and put new seals in. My point is even rebuilt parts can be defective. Wasted a LOT of brake fluid on this one!
David Teitelbaum

[stevedmc]

A replacement piston assembly is the cheapest and easiest solution:

http://sphotos-a.xx.fbcdn.net/hphotos-ash4/307818_454462807932308_287453354_n.jpg

[DMC5180]

Here is a Dorman version

14418

[stevedmc]

eBay $5 version: http://www.ebay.com/itm/80-85-Jeep-AMC-Dorman-Brake-Clutch-Mas-Cyl-Rep-Kit-CMK351936-/250851642207?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a67ec4b5f&vxp=mtr

[ramblinmike]

A replacement piston assembly is the cheapest and easiest solution:

http://sphotos-a.xx.fbcdn.net/hphotos-ash4/307818_454462807932308_287453354_n.jpg

That's the one I bought. The replacement spring felt very weak - the pedal didn't bounce all the way back like it should. I swapped the springs and its been great.

[Chris 16409]

Here is a picture of the threaded hole with the mating surface. It looks really jagged to me. I was getting fluid leakage from the threads.

I don't have a seal problem, just the jagged edge as shown in the picture I posted. Could air enter in this location if the seal isn't tight?

[stevedmc]

That's a flare fitting. Tapered sides provide the seal.

If you don't see any fluid forced out under pressure the seal is fine.

[David T]

Rebuilding the cylinder is always going to be the cheapest option but if the bore of the cylinder is pitted it will leak. Your choices now become either replacing the cylinder or having it sleeved. Probably cheaper at this point to get another cylinder. Flush the brake fluid every other year and the clutch and brake systems will last a LOT longer. Once the brake fluid gets dark and thick looking it is already past due.
David Teitelbaum

[stevedmc]

That is what people are complaining about -- replacement cylinders from DMCH aren't any good (fail prematurely).

[David T]

As Steve and Bill pointed out, there are other sources besides DMCH for master cylinders. If your cylinder is all pitted inside a rebuild kit all by itself is not going to help.
David Teitelbaum

[Jeffu]

Yeah, what stevedmc said. When you buy a new one you just expect it will work for at least a couple of years.

[BABIS]

and what about the new clutch slave cylinders from DMCH?

[Chris 16409]

Here's a picture of the bore out of my DMC-H cylinder.

[bikergurl2000]

Is that what pitting looks like? I don't see any holes but it looks like some of the metal rubbed off.

[ccurzio]

Is that what pitting looks like? I don't see any holes but it looks like some of the metal rubbed off.

Why are you interested?

[DMC81]

Here is a Dorman version

14418


I replaced mine with one from DMC, seems to be working great. Whats the part number for the Dorman kit?

[DMC5180]

whats the part number for the dorman kit?

cmk351685

[David T]

From the pictures it looks more like scuffing than pitting. Pitting looks like small round craters that are rough and raised. Those pictures look like aluminum scuffing on steel. It should clean right up with just a touch of a cylinder hone.
David Teitelbaum

[bikergurl2000]

I just wanted to know if scratches like that would be a problem. I tend to ask questions so I can learn. Most chicks never ask questions about cars but I'm different. Sorry.

[ccurzio]

I just wanted to know if scratches like that would be a problem. I tend to ask questions so I can learn. Most chicks never ask questions about cars but I'm different. Sorry.

No worries, no apology necessary. Just trying to make sure you're on the up and up.

Sorry for butting in. Carry on.

[Exolis]

I replaced my Master and Slave cylinders in 06, got them from DMC-FL and haven't had a problem with it or the lines since.

[Sidaries]

I replaced my cylinders in 2009 bought from Ed (Uding, not Bernstein) and no problems since then.