Interesting problem...

[painterdave72]

my clutch has started acting up.. if i hold the pedal in it will eventually seem like it bleeds down and the car will creep into gear... i do not see anything leaking at either the slave or master and the resavoir is full.. i bled the slave a few times and it just seemed like fluid came out.. could the slave just be leaking internaly slowly??? kind of annoying cause i wanted to drive today...lol..dave...ps.. both the slave and master are about five years old.. also the clutch and throw out bearing etc are the same.. and only have about five thousand miles on them.. i also have the stainless line so rule that out.. .

[DCUK Martin]

The master leaks into the cockpit and soaks into the foam under the carpet.

[painterdave72]

the master is not appearing to be leaking because it is dry ....

[content22207]

If fluid gets past either piston, you will see it outside the system -- master cylinder inside the car, slave cylinder on the bellhousing. The only place fluid can leak and not be visible outside the system is the stopper that seals off the reservoir, although if even that is leaking bad enough you will see fluid shoot out the hole in the reservoir cap.

Bill Robertson
#5939

[painterdave72]

nothing is leaking.. and the resovoir is full.. i have heard that seals can fail internally and cause a leak inside... what else would it be??? it goes into gear and all fine in the garage.. just when u hold the clutch pedal in for about ten seconds is when it lets up close to the floor and hard to put out of gear.. it evenutally creeps forward or back in gear depending on first or reverse and i have to shut it off and pump the pedal to get it to release...

[content22207]

The only internal seal is the reservoir stopper. On the other side of the other two seals -- master cylinder piston and slave cylinder piston -- is the outside world.

Do you still have the original plastic clutch line? Conventional wisdom is that it expands under pressure (other car companies use plastic lines no problem, but their runs are shorter).

Bill Robertson
#5939

[painterdave72]

plastic line anymore.. it was perfectly fine till two days ago. it was very hot then... and hot today. i could see that if the line was the plastic one but i have a nice stainless braided one.. the only thing i can think of is the slave is very slowly leaking and letting in a minute amount of air when under pressure...

[David T]

If you are having problems withe the clutch hydraulics there are only a couple of things that can happen. The hose from the reservoir to the clutch master, the clutch master, the hose from the master to the slave and the slave cylinder. If the pedal won;t stay firm the fluid is either leaking out of the system or it is leaking back from the slave to the master (an internal leak). You can start with replacing the master cylinder if you are convinced the slave is not leaking and there are no external leaks. If you are not losing any fluid the reservoir will remain full. If the brake fluid is dark and thick you should replace the slave too.
David Teitelbaum

[painterdave72]

I am pretty convinced that the slave is not leaking. i will get under there tomorrow.. so Dave you recomend replaceing the master first?? that is not leaking either. except maybe internally like you said.....

[Jacko]

In my years of ownership I have had the exact same issue as you describe. No external leaks and the clutch slowly engages. Each time (2 or 3) I surmised the master was 'pumping through itself' ... leaking internally. In each case I replaced the master cylinder and the clutch was back to normal.:Headspin:

EDIT: Just noticed you wanted to drive the D today ... it may be too late now but it's okay to drive it. You just have to do your clutching & shifting quickly. :biggrin:

[painterdave72]

another 100 dollars....lol... i will have to order one this week then!!!!

[content22207]

DeLorean clutch hydraulics:
2318

There is no way the master cylinder can "leak internally" -- it is nothing more than a simple hollow tube with a piston sliding though it. If it leaks, it is either going to leak past the piston onto the floorboard of the car, or it is going to leak past the stopper into the reservoir, both of which are external to the cylinder itself.

Bill Robertson
#5939

[painterdave72]

interesting.. if it leaks itself back into the resavoir then maybe that is why the fluid level doesnt go down????

[Jacko]

DeLorean clutch hydraulics:
2318

There is no way the master cylinder can "leak internally" -- it is nothing more than a simple hollow tube with a piston sliding though it. If it leaks, it is either going to leak past the piston onto the floorboard of the car, or it is going to leak past the stopper into the reservoir, both of which are external to the cylinder itself.

Bill Robertson
#5939Okay, we can call it something other than 'leaking internally". What I'm saying is this: I have, on three occasions (I looked in the log), had the exact same symptoms as Painterdave describes. In each instance I replaced the Master Cylinder and the clutch was normal again. Painterdave, I assure you that replacing your master will cure your problem.
Bill, what would you say was wrong with it?

EDIT: I just had a thought ... I'm sure I have at least one of the "phantom issue" MC's in the shop. Someone could perform an autopsy ... ??

[content22207]

http://www.autozone.com/autozone/parts/Duralast-Clutch-Master-Cylinder-Kit/1981-AMC-Spirit/_/N-ilgb5Z6o2n9?counter=0&filterByKeyWord=clutch+master&fromString=search&itemIdentifier=708172_0_0_

Bill Robertson
#5939

[painterdave72]

would that actually work to rebuild the clutch master cylinder???

[Jacko]

http://www.autozone.com/autozone/parts/Duralast-Clutch-Master-Cylinder-Kit/1981-AMC-Spirit/_/N-ilgb5Z6o2n9?counter=0&filterByKeyWord=clutch+master&fromString=search&itemIdentifier=708172_0_0_

Bill Robertson
#5939Bill, I assume the answer to my question above is somewhere in the Autozone URL. You're gonna have to point it out to me. I missed it.

[Jacko]

would that actually work to rebuild the clutch master cylinder???Yes, it's done routinely. I always go with a new one. I don't trust a rebuilt one as much as new. The slave is such a PITA that I wouldn't want to do it twice if you get my meaning. Although the master is relatively easy to replace I just feel better with a new one.

Just my 2 cents ...

[content22207]

#5939 has been driving with a rebuild kit since 2004.

I know these master cylinders like the back of my own hand. Having driven the same 4 cylinder manual transmission 1981 AMC Spirit since high school:
2320
I 100% guarantee that its clutch master cylinder is 100% identical to a DeLorean clutch master cylinder. Even the Girling part number cast into the side is the same.

Bill Robertson
#5939

[content22207]

AMC clutch master next to a DeLorean clutch master:
http://dmctalk.org/attachment.php?attachmentid=2322&d=1309844064
Pedal connecting rods are interchangeable between cylinders.

Bill Robertson
#5939

[painterdave72]

I have one of john herveys clutch master cylinders though but it should be exactly the same right???? so i can go to auto zone and get the rebuild kit???

[content22207]

John sleeves his master cylinders -- I don't know if his sleeves have the same ID as an OEM Girling bore.

Note that Autozone's computer system is confused RE: clutch master itself. If you order a complete cylinder, they send one with an integrated reservoir.

Bill Robertson
#5939

[painterdave72]

i just checked the master cylinder .it says girling and the part number on the side of it.. i dont know if it is sleeved or not. it is about five years old and im pretty sure it is from him.. it has a bellowed rubber boot on it in the car though and most of them ive seen are only the little boots.. it is also painted black near the firewall for about two inches or so...

[DCUK Martin]

letting in a minute amount of air when under pressure...

low pressure air ain't gonna get into a high pressure container.

Start by simply bleeding your system, and then check your master cylinder is completely dry

[painterdave72]

I checked with john. he didnt sleeve them a few years ago.. so i just ordered a master cylinder rebuild kit from him.. hopefully that will fix the prob.. Dave...

[Chris 16409]

Bill, how do you order the master cylinder without the reservoir then?


Note that Autozone's computer system is confused RE: clutch master itself. If you order a complete cylinder, they send one with an integrated reservoir.

Bill Robertson
#5939

[painterdave72]

well i got the master cylinder rebuild kit in the mail yesterday.. i will take it out and put the new seals in on mon and see if that fixes my prob!!!!! hopefully!!!!

[painterdave72]

installing the two new seals in the master fixed the problem... the smaller seal in my master cylinder was all spongy and had pieces missing for some reason....dave

[content22207]

If you are talking about this seal:
2684
that is the one that shuts off the reservoir. When it goes bad, you push fluid from the master cylinder into the reservoir rather than out to the slave cylinder.

Bill Robertson
#5939

[painterdave72]

that was the one that went bad for some reason...

[Jacko]

... 'leaking internally' ... if we could consider the reservoir as part of the master cylinder 'package' and a leak occurs but there is no leakage to the outside world one could describe an 'internal leak' as occurring. A seal within the master cylinder fails, leaks but shows no evidence of a leak ... fluid leaks into the reservoir.
Would it be erroneous to describe this phenomenon as an 'internal leak'?
Maybe an 'internal leak' within the clutch hydraulic system ... the only place that can occur is that small seal in the master cylinder ...

Anyone want to give me a "hell yeah!" ... or not ... :rock_on:

[content22207]

The reservoir is not integrated into the master cylinder -- it's connected by a hose that can (and often does, when replaced with the wrong kind of hose) leak. Kind of hard to consider a leak between the reservoir and master cylinder internal if fluid is dripping from that hose all over your frame and the ground.

You might as well otherwise consider a leak anywhere between the brake master cylinder and the calipers internal.

Bill Robertson
#5939

[David T]

When rebuilding a cylinder you should hone the inside bore to smooth it up and make sure you have a good sealing surface for the seals. It will also remove any roughness that may tear up your new seals. If it is badly pitted you should sleeve it so it will be the correct inner diameter because if you hone too much to remove the pits you enlarge the bore and the seals will, again, leak. A small, inexpensive brake cylinder hone available locally at any large auto store and a drill is all you need. After honing wash thoroughly to remove all dirt and metal before assembly. As you assemble all parts should be dipped into brake fluid to provide lubrication during assembly.
David Teitelbaum