Problem bleeding brakes after 929 MC install
 

Well, i got my 929 MC installed after fabricating all the new lines and what not, bench bled on my workbench prior to install. Hook everything up, start bleeding brakes.

The rears put out some air, not much - some pedal resistance.

I get to the fronts, the pedal has no resistance while bleeding and the fluid is coming out really slowly.

I do all four wheels twice, then close the last valve and push the pedal - straight to the floor.

So I do it all again, same results. I disconnected the lines and bench bled the MC on the car, a few bubbles but not much. I notice at the end of the pedal stroke a air whooshing sound but no bubbles anywhere.

After hooking everything back up again, i still have no pedal pressure, but no bubbles in the lines when bleeding either.

What gives? Do i have a bad MC? I used Robinette's guide for the install

http://robrobinette.com/mastercylinder929.htm



TIA

get a powerbleeder - works great!

LOL, i actually have one, but it's on loan to a miata track buddy :o

Mr3plus one gave me a tip on AIM, said I need to adjust the rod to the brake pedal to get it more travel. I'll try that and report back.

You probably got air in the abs control unit. That can be a real pain to get bled out. I definitely recommend a power or pressure bleeder. Good luck!

--Hank

The o rings inside the MC may be bad, pick a rebuild kit if all other solutions don't work.

The trick is to start bleeding from the MC out through every connector towards the ABS first. This will get all the air out before it gets to the ABS and the problem will not occur. Then afterwards you can bleed normally from the brakes.

I did the 929 MC this way and never had any problems.
It is the only logical way to get the air before it goes into the system.

That's how i started out bleeding actually. I've adjusted the brake rod, re bled and i get no air out of the rears or the front left, but air is still coming out of the front right. I guess I just have a shit ton of air in the ABS?

Well, it was a bad unit. I put my original new 929 MC on which I though had a bad rear port originally (my dumbass ignorance) and it works like a champ now.

Thanks for the replies.

Cool, good job man. How was making the custom line? What do you think of the mod? Is it worth it? Let us know.

--Hank

I put in a 929 mc with out making any line or bending any . I pluged one port ,welded, and drilled and taped one .

I haven't actually driven the car yet, after i got finished I still had other work to do, buy the time the car was buttoned up and on the ground, i was full of beer and too tired. I'll run it out tomorrow for a report.

I hope you mean tapped!!!

I got a bad 929 MC as well last year, and unfortunately was having a shop install it. It cost me alot of hours to have to have them just put my old one back on. I was really pissed off.

What's the point anyways? Do you guys have upgraded calipers?

All a larger bore MC does is allow you to move more fluid, but with a harder to press pedal, right?

You're correct. The point is that my stock MC was bad, and i'm going to upgrade my brakes at some point anyway so I decided to go ahead and put the 929 unit on now so i don't have to do it when i upgrade my brakes down the road.