Clutch Master Rebuilds

[Jim_Gruber]

Bugsy my '68 Sprite has a leaky Clutch Master as my carpet on the stairs from the garage will attest to. Brake fluid seems to have an affinity with the soles of Topsiders that transfers to carpet. I've got to fix this one as wife has new carpet ordered to be installed next week. And she doesn't know that Bugsy is the source of the problem.

I've heard of the issues rebuilding Lockheed Brake Masters and scratching bores, getting the sccond snap ring out, etc. How tough is it to rebuild Clutch Masters other than making sure you've got the right rebuild kit and a honing tool.

Clutch Master was new 12 years ago but other than adding brake fluid over the year, it's been leaking for some time, I've never flushed lines out. Thoughts on rebuild vs. replace.

New Brake Master and hoses will be going in at the same time.Parts are in hand and ready to go. Hopefully will cure my front brake pulling initially to one side issues. Brake hoses are 12 years old as well. Time they were replaced.Issue may be related to lack of driving.Bugsy put < 100 miles on the odometer this year due to Lake Cottage remodel Project.I worked on the cottage every weekend instead of having fun. Will do things differently next year.

 

[bug_sixty]

You will have more info when you pull the Master. Most leaks are from rust pitting on the cylinder walls not the rubber seals... All of us should check the moisture content of the fluid every spring and flush and replace as needed. Not sure where the test strips are sold these days...

 

[bug_sixty]

more...Adding fluid doesn't work cause water is heavier and sits at the bottom and does what water does..

 

[Jim_Gruber]

Thanks any replies on success of honing and redoing CLutch Master?

 

[Gerard]

You will have more info when you pull the Master. Most leaks are from rust pitting on the cylinder walls not the rubber seals... All of us should check the moisture content of the fluid every spring and flush and replace as needed. Not sure where the test strips are sold these days...

Ditto.

The clutch MC, unlike the brake MC is very easy to rebuild, but if the has pitting, then I wouldn't bother putting a seal kit in unless, in the unlikely event, you're making a temporary fix. Either get a new one or have it sleeved by Sierra. It'll cost you less to sleeve and unlike buying a replacement, you will never have problems with it again, no matter how long it sits. Changing the fluid is even more important in these tin can reservoirs because unlike the cast or plastic ones, it doesn't take long before a pin hole can develop due to the thin metal.

I'm currently replacing a similar style brake MC in an MG 1100. They use the same style MC's as the Mini's. The reservoir is a similar tin can. This is a car that was completely restored 6-7 years ago, and I believe the MC was either new or at least re-plated. The guy that rebuilt it used silicone fluid in the system. Ironically, this was the cause for it's demise. The owner, being under the belief that silicone fluid does not absorb water, the fluid has never been changed. While the fluid does not hold water in suspension, moisture still gets into the system. When I pulled if from the car, I found some gelatinous rust had formed along the seams at the bottom, and a pinhole leak had formed, likely with more to come.. Everything else is pristine, so it's apparent that some water pooled in that area. I'm putting in a brand new MC today.

 

[bug_sixty]

Wow, didn't know that about silicone.. why even switch if that's the case...

 

[JPSmit]

Thanks any replies on success of honing and redoing CLutch Master?

I think it is always worth a try - the kit is sooo much cheaper than a new onw. certainly pull it apart and look. Pitting will be abvious.

 

[Jim_Gruber]

Thanks guys, seals it is. Anyone know what size honing stone is needed?

 

[nomad]

Gerard:

I'm personally sold on Dot 5 silicone. A friend has my 72 MGB that had to have its entire brake system rebuilt in the late 70's. That is when I switched it to silicone. Brakes still work fine and I don't believe they have ever even been bled. Silicone is sort of oily and I would not expect it to have a gelatinous rust formation but I have seen plenty of that from Dot 3. I'm wondering if maybe some of that was added at some time.

My .02.

Kurt

 

[Gerard]

Gerard:

I'm personally sold on Dot 5 silicone. A friend has my 72 MGB that had to have its entire brake system rebuilt in the late 70's. That is when I switched it to silicone. Brakes still work fine and I don't believe they have ever even been bled. Silicone is sort of oily and I would not expect it to have a gelatinous rust formation but I have seen plenty of that from Dot 3. I'm wondering if maybe some of that was added at some time.

My .02.

Kurt

Someone did add some. The car was recently sold to someone in my neighborhood and upon purchase too it to a British Car shop to be checked out. They topped up the brake MC with Glycol. But that was only two months ago, so that kind of damage could not have occurred in such a short period of time. The real unfortunate part of the whole thing (and why I know glycol was added) is that when the pinhole leak started, it dripped fluid all around the base of both MC's and ruined the paint anyway.

Anyway, I think people misinterpret the "silicone does not absorb moisture" as, "none gets in there", as opposed to the fact is hydrophobic, meaning it does not hold water in suspension. What silicone <span style="text-decoration: underline">does</span> hold in suspension is air. I have it on good authority that even a factory sealed bottle can hold as much as 12% air. If you shake the bottle, it's even worse. This doesn't pose so much of a problem in a small system as it does in a large one, but does contribute to the spongy feel some people report.

As a side note, if you think a silicone based system, even from new as this one was, remains clean inside, tomorrow I'll post a pic of what I flushed out of the system today. I suggest if you use silicone, you change it out every couple years.
From what I observed, I can't draw any other conclusion than water was pooled at the bottom of the reservoir, just like you would see if you had oil and water in a jar.

 

[nomad]

Point well taken, Gerard, but I'm still sold on Dot 5. Agree that what ever one uses it should be bled out every now and then. I'm running it in 2 british cars right now and have 2 with D0t 4. The comparison I make is that the dot4 gives a little faster brake action in my opinion since its thinner. The dot 5 sponginess which you mentioned I believe is due to the system still having air bubbles in it. I have experienced it and it went away with time.

Again, my .02.

Kurt.