master cylinder flub up??

[finally]

I tried rebuilding both master cylinders and not feeling good about the results. Tried ordering from NAPA since they listed they had the rebuild kits for my Series 2. Seemed to fit the Clutch (lockheed 3/4") but the one they sent for the brake (girling .70") actually looked identical to the clutch one but just a different brand.

Anyway, got a brake MC repair kit from one of our trusted suppliers and rebuilt both. Unfortunately, the clutch MC seems to provide zero pressure now (possibly because I haven't bled the system yet maybe???) and the pedal goes all the way to the floor. I thought I'd get at least some pressure though. Thoughts anyone?

The brake MC is extremely tight and doesn't return very well after depressing the pedal. This seems to be getting better now that I've repeatedly pumped the pedal but I'm still not 100% comfortable. Is this normal??

Thanks!
Jared

 

[mikephillips]

The pedal will flop loosely until bled. Remember you're pushing against air until that's complete and there's not enough compression on it to provide much back pressure. As for the master, it should be tighter than before the rebuild since the new seals will be tighter. If you're is incorrect though is hard to say without being able to try it. Is it also waiting to be bled??

 

[finally]

Neither brake nor clutch MC have been bled yet. Any special trick to bleeding the clutch or is that straight forward?

The brake MC - The new seals made the piston fit very tightly so the piston wasn't coming back out to original position at a normal speed. Its starting to come back out faster now but will have to see if it starts working reliably (before I drive it of course!).

I caused a little brake line leak in reinstalling so will replace that and try bleeding both this weekend.

 

[mikephillips]

Once the cylinder and bore get wet from the fluid you'll probably be ok. As for the clutch, it can be a bit of a hassle to get all the air out. Just be sure that the line is on the bottom of the slave and the bleeder on the top.

 

[Alpine 1789]

Unfortunately, the clutch MC seems to provide zero pressure now (possibly because I haven't bled the system yet maybe???) and the pedal goes all the way to the floor. I thought I'd get at least some pressure though. Thoughts anyone?

I have always found it extremely difficult to bleed the clutch master cylinder. While the problems getting all of the air out have been well documented, my problem has always been getting it started. No amount of pumping seems to build up any pressure after a rebuild or complete system draining. It sounds like you are having the same problem. The only thing that has worked for me in the past is to "vacuum" some fluid all the way through the lines. While today I do this with a vacuum pump on the slave cylinder with the bleed screw open, in the past I just attached a clear hose to the bleed screw and sucked the fluid through myself. Feel free to add your own comments here, but this has worked for me in the past.

 

[Eleven]

Clutch

I just finished my clutch master and installed a rebuilt brake master over the weekend. I had the same problem with the clutch so put it on the bench, filled it with fluid, pumped it down, stuck my finger over the hole,let it rebound, removed said finger and pumped again. Got a great squirt after two or three of these. Reinstalled and it bled fine from then on. Needed priming ( I think Jan tipped me on that). The brake master is now giving me the same fits, may try that again but it was harder to install and don't want to remove it again or squirt fluid all over the car. Hope this helps.

 

[finally]

Done!! I replaced the problematic line and bled the brakes. Very firm now!

I also got the clutch bled out as well - well, at least I've got good pedal fell and clutch movement. Don't think I got it perfectly but its working well so that's fine with me.

First time trying all this - quite an experience but not too tough. Definitely not interested in doing this kind of work everyday though... I prefer my desk and wining and dining of customers!!

 

[jumpinjan]

Yeah, those bleeding problems can be minimized quickly by bleeding the M/C on the bench, insert a 3/8-24 bolt in the M/C (to keep the fluid in) and install.

 

[Eleven]

Ref: The Brake Master

Got mine all bled and working something wonderful except the moment it didn't. Slack pedal rolling off the freeway to a line of stopped cars...now that is excitment!! Gave it a pump and back it came to normal. Did it one more time. Have decided that since it didn't go soft, it just went slack, that the piston stuck on me. (I rebuilt an older .70 unit, noticed no problems in the bore). So, my questions are: 1) Do I go out in the garage with a beer and pump the pedal a couple hundred times to wear the seal in or 2) Pull it all out and take some 600 grit to the bore and try again? Thanks!

 

[britbeam]

Done!! I replaced the problematic line and bled the brakes. Very firm now!

I also got the clutch bled out as well - well, at least I've got good pedal fell and clutch movement. Don't think I got it perfectly but its working well so that's fine with me.

First time trying all this - quite an experience but not too tough. Definitely not interested in doing this kind of work everyday though... I prefer my desk and wining and dining of customers!!

You keep on playing with Alpines and you will soon forget the wining& dining. It gets in your blood. These problems are opportunities to learn and expand your abilities. Good for you. That desk will be there when were all gone. Come to think of it if we do a proper job on the Alpine they will be here for someonelse to enjoy also.
Dwain V6 Krazy