Jump to content
  • When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Do I need a new master cylinder?


Guest Anonymous

Recommended Posts

Guest Anonymous

Brakes won't release. Both fronts are locked, rear are tight enough to be difficult to turn. I rebuilt the front calipers recently, installed new rotors, pads and flexiblie lines. This evening I cracked a bleed valve enough to relieve some pressure, and worked the pads out on the drivers side. I was able to press the pistons back in with little effort, but of course one goes out when another goes in. Putting a pad in I can't get the pistons to return as a unit - in other words the brake fluid won't go back up the line.

My tentative diagnosis is I need a new master cylinder. But I've never seen a master cylinder fail this way.

Alternate opinions? Is this something you've seen before?

I tried to save kittens, and the archive did give me some hits, but in those cases it was binding calipers and working the pistons in and out a few times freed them up. I think my calipers are ok.

Link to comment
Share on other sites

Guest Anonymous

not in an 02, this car was involved in a front end hit and the

master cylinder moved inwards into the booster, so the

plunger that actuated the hydraulic lost some of the travel and

would not release the pressure on the way back, solution was

to put some washers to reestablish the geometric relationship

(not ideal, but it worked for this particular pos car). I still don't

understand it well, hope this helps.

Link to comment
Share on other sites

Guest Anonymous

how old are your brake lines? Original 02 rubber brake lines are known to swell up internally over the years, and eventually start closing up. What happens then is that the fluid pressure builds up at the wheel cylinders, but will not release. It does seems strange, however, that this would happen to you with all four lines...

Chris B.

'73 ex-Malaga

Link to comment
Share on other sites

Guest Anonymous

If you can reproduce the problem, try unbolting the master from the booster. The booster depends on some funny little valve and a diaphragm that pushes hard on the master when the linkage opens the valve. If it gums up, the master can't relax. Another diagnostic is to disconnect the booster vacuum and see if the problem recurs. Be careful, you have to stomp extra-hard on the pedal if there's no vacuum.

Mike

Link to comment
Share on other sites

Guest Anonymous

- rubber brake lines in front were acting like a one way valve.

P.O. had spent $600.00 on new front brakes but did't replace the hoses. I thought the car was a dog until I replaced the hoses and drove it w/out the front brakes being on constantly.

Link to comment
Share on other sites

Guest Anonymous

That may have confused the situation a bit, since I don't know if it was the M/C or the booster that didn't release.

But I know it wasn't flexible lines, because they are new.

So, if the booster valve is "gummed up" can I clean it and get it to release? Or is this "the end?"

Link to comment
Share on other sites

Guest Anonymous

No vacuum on booster. Pumped brakes, locked. Had to loosen M/C on booster to release. Tightened M/C mounting nuts back up, brakes locked again. Loosened, brakes released. Obviously the actuator rod from the booster is extended and won't release.

The brake pedal itself is coming back up all the way, and the linkage is contacting the brake light switch, so I think it is not a case of gummed up linkage.

Anyone got a spare booster?

Link to comment
Share on other sites

Guest Anonymous

But as of 10 minutes ago I am the successful (and only) bidder on a Tii booster on eBay. So this problem should be solved. And when I install that Manx sidedraft and DCOE 40, I'm set :-)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • BMW Neue Klasse - a birth of a Sports Sedan

    BMW Neue Klasse - a birth of a Sports Sedan

    Unveiling of the Neue Klasse Unveiled in 1961, BMW 1500 sedan was a revolutionary concept at the outset of the '60s. No tail fins or chrome fountains. Instead, what you got was understated and elegant, in a modern sense, exciting to drive as nearly any sports car, and yet still comfortable for four.   The elegant little sedan was an instant sensation. In the 1500, BMW not only found the long-term solution to its dire business straits but, more importantly, created an entirely new
    History of the BMW 2002 and the 02 Series

    History of the BMW 2002 and the 02 Series

    In 1966, BMW was practically unknown in the US unless you were a touring motorcycle enthusiast or had seen an Isetta given away on a quiz show.  BMW’s sales in the US that year were just 1253 cars.  Then BMW 1600-2 came to America’s shores, tripling US sales to 4564 the following year, boosted by favorable articles in the Buff Books. Car and Driver called it “the best $2500 sedan anywhere.”  Road & Track’s road test was equally enthusiastic.  Then, BMW took a cue from American manufacturers,
    The BMW 2002 Production Run

    The BMW 2002 Production Run

    BMW 02 series are like the original Volkswagen Beetles in one way (besides both being German classic cars)—throughout their long production, they all essentially look alike—at least to the uninitiated:  small, boxy, rear-wheel drive, two-door sedan.  Aficionados know better.   Not only were there three other body styles—none, unfortunately, exported to the US—but there were some significant visual and mechanical changes over their eleven-year production run.   I’ve extracted t
  • Upcoming Events

  • Supporting Vendors

×
×
  • Create New...