pedal goes to floor just replaced master cylinder and vacuum bleed brakes cannot get the air out car has sat for ten years with new calipers have the seals in the calipers gone bad all lines and fittings are tight and there are no leaks

 

piston seals in calipers and / or caliper bores are shot

 

Dogg your post would be SOOO much easier to read, if you slowed down and made sense!

 

Did it sit for 10 years with new calipers, or did it sit for 10 years and you just put new calipers on it?

I'm not saying this to be a smartazz, but some basic punctuation would make your post more effective.

One thing I use to bleed brakes is a pressure bleeder. You can make one very cheap, but you need an air compressor to use it.



Click on that picture for instructions on how to make one. My brake pedal is rock hard as a result of that thing.

 

I just bought a pressure bleeder system from Motive last week and used it today. I gotta say it is the best thing ever! I could do the job alone and now have the best feeling brake pedal I could ask for. I also did a bench bleed of the master cylinder in the car with a kit before pressure bleeding the system. Links to both tools are below.
http://www.midwayautosupply.com/deta...ption.asp?2273
http://www.motiveproducts.com/02bleeders.html

 

sorry about my haste but that is what im use to at work cannot ever please them. the car has sat for ten years with new calipers on it. between the kids college, jobs moving over seas ,only home one day a week and a problem in the body shop it is finally done. put on a new master cylinder yeasterday thinking that was it and vacuum bleed the brakes. no leaks in system but still have no pedal cannot get air out of system.

 

Did you bench bleed the m/c before install?

 

yes I did, the brake fluid that came out of the lines was real dirty so also flushed system. would the seals go bad from sitting so long?

 

The seal should be ok if the car was in a dry environement. I think you need to bleed some more the master cylinder.

You can get an assistant to pump the pedal and unscrew the tube fitting at the master several time. Other than that, bleed the left front wheel, then the rear right wheel, then the right front and the left wheel. That order will help with the proportionning valve that block the fluid flow from front to rear in case of a hose brake failure.

If there is no leak, you should be able to get the pedal real firm. Keep on pumping!

Stephan

 

Did you get a new master cylinder or a rebuilt unit? I have heard many horror stories about rebuilt units. Recently read about someone who went through 4 rebuilt MC's before getting a good one. I hope this is not the case for you, but of nothing else works, check this.

Good Luck!




[Modified by ACECO, 2:43 AM 7/4/2004]

 

I went through that frustration last week. I learned that the pushrod from the pedal to the piston in the master IS adjustable, and needs to be checked. If there is not the required 1/16 th inch clearance in the pedal travel you will probably not get it to function right. Also learned that even brand new (not rebuilt) masters are not always functional. I spent almost a week thinking, it can't be my brand new master cylinder. finally put the old one back on and now I finally have brakes.

 

Try something called a MITYVAC... it sucks the fluid out from bleeders and it's a one man job. Have one myself ...works great on bike brakes too which can be a pain. Great tool that can be used for other garage chores too. Do a google search on it. About to pull mine out soon since I have a caliper leaking now and needs a rebuild. Good luck!

 

Hi

If it just sat for 10 years, the caliper piston's lip seals might be shot ( deformed ), so sucking fluid out htorugh the bleeders only sucks in air through the caliper piston seals.
Even if the calipers do not show any leakage, they might still easily let air pass in.
I mus obmit that I never had any problems bleeding Vette brakes so far, not even with the old pedal pushing method and can't understand all this problems constantly reported on this forum. Am I just lucky here ?

Rgds. Gunther

 

I had a similar problem, replaced the master cylinder 2 times, kept bleeding the brakes, but it would go bad a day later. Took a rear caliper off and noticed a tiny amount of fluid on the back of the brake pad. Changed the caliper, bled the system ,problem solved, so I think you should check the calipers.

 

My car has been sitting for 10 years like yours. I saw some fluid leaking out of the original calipers so I went ahead and replaced the master/calipers/hoses and went to DOT-5. I have not had any problems bleeding on other cars after a system overhaul but this Vette system is giving me a little trouble.

My Motive products pressure bleeder is on the way and should be here some time this week.

The order you bleed them in is different on a Vette. The service manual may tell you the right order. It is different than what I have done on all other cars.

The fronts are pretty simple but the rears might be a little tricky. They have 2 bleeder screws per side. I suspect the inner one needs to be bled first. If you try to go with the outer one first, the air bubbles will tend to migrate from the inner caliper half to the outer caliper half only a little at a time during the process. The bubbles will probably trickle from the inside to the outside slowly so this will be a long process if you try to do the outer first. I think it would be better to do the inner first, then the outer.

I think the pressure bleeder will help prevent the air bubbles from floating backwards between pedal pumps. The constant flow seems like it would be better than on-off-on flow where the bubbles can float backwards between pumps.

I have a Mighty-Vac and I think you can pull air past the seals using it if you pull too much vacuum.

This is not advice from an expert in any way but I hope it helps.

-Mark.