Master Cylinder question, brake fluid leak

[skittishsynapses]

So my brakes have been slowly slipping the last few months. Of course like a dummy I didn't think I was low on fluid until a couple weeks ago. I played it dumb and called my mechanic, asking him about the brakes feeling mushy and not having any stopping power. I put in some fluid and take her in the next day for a quick look over. His verdict was I needed a new Master Cylinder. He pointed out the leak which is coming from what connects the front left brake line to the MC. It looks like a 1 in wide, 1.5 inch tall round cylinder that attaches to the MC. I have no idea what that is, but that looks like where the leak is coming from. The guy quoted me at 50 for that part, and called it a valve, no idea what it actually is. Anyone care to name it? (sorry for the lack of photos, I'm on my lunch heh) Anyone know where I could buy it? Online would be acceptable, unless you know a place in the Los Angeles area.

Other thing, so the leak seems a bit worse as of the last day or two...I have a couple bottles of fluid as a temp solution but yeah, I need to get the parts. Anyone's guess why that particular 'valve' wore out? I'll try to get a photo or two up tomorrow. Thanks everyone!

Oh shoot before I forget, I have an 87 cabby. I'm so happy, she's survived her first winter/spring rains with a new top. That had nothing to do with anything

Update: so here are the photos of that valve in question - Break proportioning valve. managed to find something that looks like it online, but I can't find any documentation that supports their even being there! http://www.amazon.com/OES-Genuine-Brake ... B001G7S6U2

Or is it a residual pressure valve? roomie found something on ebay just now that looks similar. Would anyone know if it is a 2lb or a 10 lb valve? Anyway here are the photos, and notice the leak coming from it...

[eric4321]

In my experince a leak like that is probably a loose line or valve or both. Usualy when the master cyl is bad it leaks from where it bolt to the booster. (The big black drum behind the master). Those valves are usualy dealer items but I don't know for sure on Cabbys. Also you realy should not drive with leaky brakes. Even if all you do is tighten the line and valve you will need to bleed the air out of the brake system. To the best of my knowledge those valves should not need replacing unles they get damaged in the fittings. That will happen if the lines were not instaled properly but will usualy leak imediatly after that happens.

[Briano1234]

In my experince a leak like that is probably a loose line or valve or both. Usualy when the master cyl is bad it leaks from where it bolt to the booster. (The big black drum behind the master). Those valves are usualy dealer items but I don't know for sure on Cabbys. Also you realy should not drive with leaky brakes. Even if all you do is tighten the line and valve you will need to bleed the air out of the brake system. To the best of my knowledge those valves should not need replacing unles they get damaged in the fittings. That will happen if the lines were not instaled properly but will usualy leak imediatly after that happens.

Two thumbs up on the loose line or loose valve to the body. I personally have never seen a bad proportional valve ever. Matter of fact I usually clean them out with brake-clean when I am replacing the the MC.

They are on the front left and right rear of the master cylinder, and are used to control the pressure to the rears to prevent them from locking up. The Master cylinder is such that there are 2 chambers. One chamber controls the left front and right rear. The other is the right front and left rear, so that you have controlled braking.

[skittishsynapses]

Apologies for the belated response, been a bit focused on building a new computer. heh.

So I cleaned around the valves and the MC, added some fluid and let it sit a day or two. The leak is coming from the black rubber seal/gasket/washer (which you can see in my said photo..sorta) towards the top of the valves, and at the bottom of one where it meets the MC. I'm inclined to believe you guys about things not being tightened. The rubber at the top before the large screw top that connects the brake line seems like its soft. Is that just a rubber washer of some sort? I don't see or feel any leaks coming from the MC or the reservoir. If I had to ask a mechanic to see if they'd reuse the old valves, what would I say? Thanks everyone!

[Briano1234]

Well, to be honest, try pushing down on the master cylinder res. They can "pop" out of the rubbers grommets that hold it to the master cylinder.

Now:
A new or remanned m/c is @ 70 bucks or less.
2 new Calipers @ 20 bucks each.
Hawk performance pads (pep-boys) discontinued price 18.00
Rear drums 20 bucks each (2 needed)
Rear Wheel Cylinders 20 bucks each (2 needed)
Rear Shoes 24 bucks
Rear Wheel Bearings, inners and outers 20 bucks per side
Rear oil seal 2 needed 10 bucks.

For less than 300 bucks for all the common parts you can replace everything on your brakes yourself
That is not including the cost of a quarts of Synthetic fluid.

Now if the Calipers aren't leaking you don't need to replace them.
If the rotors are good you don't have to replace them... so parts are subjective.
Same for the rear drums and bearings, but it is nice to know they are new,and you don't have to worry about them for a bit.

You will need some brake line flare nut wrenches, but basic tools and a Bentley/Haynes will get you going.

Brakes are the number 2 safety Feature of your car. Your life Depends on them.
The number 1 safety feature of your car is YOU.
If you know there are problems, and chose to ignore them, then the fault isn't the Brakes, it is you.
If you get in a wreck, and they find out that you had a issue, then your insurance can choose to deny coverage, and
the other folks may sue the pants off of you. You can also get a ticket for failure to maintain your car. So...with that said... the
choice is yours..... (yes I am a butt hole).

[skittishsynapses]

haha, no worries. I get what you're saying. I'm just rather nervous about the doing brakes yourself deal since well, as you said it, it's your life. I'm not positively sure I'd trust myself with my life like that. lol. but then again 400 dollars to have someone just replace the mc and the valves seems ridiculous by comparison. What throws me for a loop is how to bleed the brakes since from what I've read it needs to be pressurized to keep air from leaking in. Which seems a bit out of the range of what I can do. As far as that initial mechanic's check up a month ago could tell, none of the parts you listed needed replacing, just the leak from the valves to the MC, and his suggestion was just to replace the MC now to cut down on future costs. Then I have you TR folk saying hey, it could just be your lines are loose, though not sure why both proportional valves would be leaking. but I forget who said I'd need to bleed the line if I tighten the lines....again not sure how to do that. I am interested in doing this myself but I also dont want to screw up my car and cause further repairs..lol. But I want to say thank you because I do appreciate these forums!

[Briano1234]

My how to build your own power bleeder:
viewtopic.php?f=27&t=2135

Or you get an assistant and have them depress the pedal 3 times, then hold it.
Open the bleeder nipple and using a hose on the nipple to a bottle, then close it and the
assistant can then release the pedal. Pump 3 times and repeat until all the air bubble are out.
Repeat for each tire.

[kamzcab86]

but I forget who said I'd need to bleed the line if I tighten the lines....again not sure how to do that. I am interested in doing this myself but I also dont want to screw up my car and cause further repairs..lol.

Bleeding the brake lines is easier than replacing those blasted drum brakes... in my opinion. You can go the manual, two-person route or build Brian's power bleeder, or you can pop down to Sears and buy a MityVac to vacuum bleed the brakes (and use it for other things as well). The procedure is well outlined in the Bentley Service Manual. Make sure you have new brake fluid on-hand and make sure the fluid reservoir doesn't go dry as you bleed the system. Test drive the car around your neighborhood... slow stops, panic stops, etc. before heading out on the highways and biways.

[skittishsynapses]

okay, so after a 2nd trip to the mechanic, they couldn't find a proportional valve for my cabby. But I'll agree with the comments thus far, they don't appear to be bad. For once I think my mechanic was trying to hustle me by saying he was going to try to swap out my MC, valves and lines with a different model. And I'm thinking, Im sure their parts guy that called me the other day to say they couldn't find the valve would have checked different models. When asked about tightening the valve, the mechanic avoided the subject. Gave me the exact same quote as last time, which makes me think he's full of bull. Especially when asking me to leave the car 2 days, not today a friday, but during the week.

Now, I don't know why I didn't ask my 70 something yr old gearhead neighbor (he was all about the muscle cars until his health got too bad to work on cars) until today but I figured I'd ask his opinion. He did something my mechanic didn't do (which makes me wonder why the hell not?): cleaned around the valves, and had me pump the brakes. Low and behold, the leak wasn't from the bottom of the valve like I thought, but from the o-ring at the top. He also pointed out that the edges at the top of the valve were rounded, so someone had mucked with it before (previous owner). He said my best chance was to find the part at a dealer in LA (but it's not likely) and see if they'd work on it (though the dealer near me said they'd only work on post 1990 cars). His suggestion was really because he wasn't too familiar with vws and what course of action he could recommend.

Now my questions....

Do I try to find the valve at the vw junk yard I go to since it's rare to find? Why would it be leaking at the area of the o ring? What course of repair would anyone here suggest? I gotta thank you guys for the help this far. Let me say the car brakes just fine as long as she has fluid, so for now I'll hold off on the other suggested repairs since that doesn't solve my fluid problem.