I think I have a leak near the master brake cylinder, is this bad, or fixable? Options

[914 RZ-1]

I am replacing the calipers on my car. After pumping the old fluid out, we realized the soft lines needed repair (they were fine before). Now, there is a link under the car that appears to be coming from the master cylinder:



The dark areas are wet with brake fluid.

Here is a closeup of the master cylinder. The dark areas are wet. The only spot that is not wet (yet) is the lighter area on the lower left:



I have checked the reservoir at the top and it is fine. The fluid is coming from somewhere down here.

Please advise!

Thanks!
-Jeff
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[Craigers17]

Just to double check things, if you have carpet, I'd pull it up and look under the pedals/pedal board area, and see if you have any brake fluid pooling in there. If not, I'd check the connections between the hard lines and MC in that area....make sure that they are tight.

[914 RZ-1]

Here's a view under the carpet. It's wet. There's a bit of fluid coming out of the rubber cap behind the pedals also.



Are the 19mm master cylinders a good replacement or should I stick with the 17mm? Pelican has FTE and ATE brands. Which is better?

How hard is it to rebuild these with new seals?

[brant]

You need to pull the pedal board
Then the rubber seal where the plunger goes into the master cylinder

If it’s we under the rubber. Then replace MC
If it’s dry then it’s the reservoir leaking down the tubes or chassis
Surprisingly. My reservoir cracked and the fluid followed the chassis seam down and leaked the same as yours. However it will be dry under that rubber seal on the MC plunger

[Craigers17]

Based on that last picture, at a bare minimum, I don't think it would be a bad idea to pull out that pedal cluster, clean up that floorboard, remove all the surface rust and get some new paint and primer on it before you put everything back in. My guess is your MC is hosed.....I know everyone likes the 19mm, and I replaced mine with one a few years ago. But, personally, I liked the 17mm better.

[Mikey914]

1st, yank this out and clean up the fluid. I'd personally de-grease the metal and hit with POR15. I don;t think the MC is toast. The pattern of fluid indicates a leak from the top.
It could be a simple as the rubber intake lines aren't pushed in all the way.
Do check the lines coming down.

When the hoses fail (and many did as the hose MUST be hydraulic rated hose) as wrong ones that look the same get used, this is what it looks like. Other than the clean up, this might be easier than you think.

You mentioned the soft lines needed to be replaced, I suspect this is the issue. The material is significantly more expensive, but you don't need mch. I have both here for $12
-https://914rubber.com/new-brake-hose-9mm-set-of-2

Sorry no picture, I'll ask Blake to get it up.

-Mark

[930cabman]

Time for a new Master Cylinder

[914 RZ-1]

Yeah, I'm gonna clean this all up: pedal cluster, brake MC, floor. Looks like my lovely wife is not getting the garage back as soon as I told her.

Are there rebuild kits for MC's or does the whole thing need to be replaced? I'm guessing the seals are the only thing that really needs replacing, unless the metal is somehow bad.

[flyer86d]

Replace the master cylinder. If your pedal cluster still has the original plastic bushings, it is time to replace them with bronze as the plastic ones swell with contact with brake fluid.

Charlie

[troth]

This was the result of a mc leak on my 911. I wiped the original paint off with only a rag. It got everywhere in the frunk so it all needed to be cleaned and primed. Huge mess. I’d call PMB and just have them drop ship you a new one. I don’t think resealing would be worth the time and effort personally.

[bdstone914]

Yeah, I'm gonna clean this all up: pedal cluster, brake MC, floor. Looks like my lovely wife is not getting the garage back as soon as I told her.

Are there rebuild kits for MC's or does the whole thing need to be replaced? I'm guessing the seals are the only thing that really needs replacing, unless the metal is somehow bad.

No rebuild kits are available. Ate stopped makibg them years ago as the bore can be pitted and will cheq up new seals.

[914 RZ-1]

How do I get the lines on the top detached from the MC? These are the ones coming form the reservoir in the frunk. I've tried pulling from the top, twisting the rubber, etc.

I can't remove the MC until I get these off. Thanks!

[914 RZ-1]

1st, yank this out and clean up the fluid. I'd personally de-grease the metal and hit with POR15. I don;t think the MC is toast. The pattern of fluid indicates a leak from the top.
It could be a simple as the rubber intake lines aren't pushed in all the way.
Do check the lines coming down.

When the hoses fail (and many did as the hose MUST be hydraulic rated hose) as wrong ones that look the same get used, this is what it looks like. Other than the clean up, this might be easier than you think.

You mentioned the soft lines needed to be replaced, I suspect this is the issue. The material is significantly more expensive, but you don't need mch. I have both here for $12
-https://914rubber.com/new-brake-hose-9mm-set-of-2

Sorry no picture, I'll ask Blake to get it up.

-Mark

@Mikey914 How do I get the hoses from the reservoir to the MC off? Is there some trick to disconnecting them at the ?MC?

And how would I install the new ones? Is installing them just a matter of fishing the new ones down?

It doesn't look like its those lines; the leak appears to be in the piston, but I may as well replace the reservoir lines as well.

Thanks!
-Jeff
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[Craigers17]

You can just pull the steel parts of those reservoir lines off the mc....you might be able to wiggle them left to right or vice versa a bit, but they just pull out(You might want to make a note on which one goes where). You'll probably need to remove the the fittings on the side and reuse them on the new one.

When you reattach the new mc to the reservoir lines, it can be a pain in the ass. Some people seem to do it easily. Not me, I admittedly struggled. Here's a link to when I did it the first time.....it probably seems convoluted, and it may appear as if I'm an idiot, which would be true, but you might find something in there useful.

http://www.914world.com/bbs2/index.php?showtopic=348755

[Garland]

Don’t forget the MC washers!

“914 World post link”


Here’s my before and after

[76-914]

A nickel to a donut your MC is toast. It will be much easier to pull and re-insert those lines if you pull the gas tank. They're a small (1mm thick) washers that you will need to keep from your old MC. They keep the lines from going into the MC too far. Don't lose them. If you do just turn a couple on your lathe. (IMG:style_emoticons/default/beerchug.gif)

[914 RZ-1]

I got it off. I just needed to pull it out a little to get some leverage. They popped off with some effort.

Thanks for the heads up on the washers. I haven't got the old rubber off the old MC; I'm guessing they are under there?

I've cleaned the floor. There was brake fluid all over that lower area. I've also cleaned the pedal assembly. I'm letting it dry out, then wire brush and some sort of anti-rust paint. Do they make POR15 in something I can brush on? I usually use Rust Reformer spray paint.

[bkrantz]

What I like to do, for removing and installing the feed lines into the MC, is to detach the lines from the reservoir. The MC can then drop down and provide enough access to make the installation easy.

And like people said above, don't forget the washers that go into the rubber bushings on the MC, before forcing the flared fittings in.

[914 RZ-1]

What I like to do, for removing and installing the feed lines into the MC, is to detach the lines from the reservoir. The MC can then drop down and provide enough access to make the installation easy.

And like people said above, don't forget the washers that go into the rubber bushings on the MC, before forcing the flared fittings in.

Yes, that's what I did. I also removed one of the brake lines. It gave me just enough room to pull the MC down to get some leverage on it.

I have a new MC on the way, too.

[Mikey914]

Sorry was working in the shop today. Sounds like you got it out. DO check the cloth hoses under the reservoir. It's not uncommon to get the wrong hoses there. You will know pretty quickly as the cloth will be "wet".

POR15 will work well here too. Got the washers if you need them.

PS stop by HF and pick up a set of these $6 pliers to put the rubber "plugs" into the top of the MC. Even if you use them just for this it will be worth it.

https://www.harborfreight.com/11-in-90-bent...6042ea1f08bd17b