update on brake issues

[JetDoc]

If you read my post a couple days ago, i was looking for a kit to rebuild my proportioning valve, after dissasembling the valve i decided to clean it all up (its alot more than a ball and spring) i found out! The bores looked good so i cleaned up the piston assy. etc. the seals looked pretty good and still soft so i reassembled the valve and reinstalled it in the car. I got in and pumped the brakes a few times and i actually had some good pedal feel until i started the car! Now i have none! I re-bled the master cylinder (i have a question about that later) and re-bled the brakes in the correct order! Still no pedal with the car running. Now to my question.... I'm not sure i'm bleeding the master cylinder correctly, my M/C has 2 bleeder screws i connected a hose to one bleeder at a time the other end of the hose in the reservoir and had my son pump the brakes and got alot of air out! is this the correct way to bench bleed this M/C? I'm really starting to pull my hair out with thing and i dont have much more to loose! The darn car sure looks good sitting in the garage but i would really like to drive it! Thanks!

[Daniel]

Sorry about the ball and spring. I thought you were a 240 until i saw your gallery photos. The bleeding method you choose will work. The fact that you loose brakes with the motor running would seem to indicate booster/ vacuum/ check valve issues. I would check to make sure you have vacuum at the booster and the hose is secure and good. Did you adjust the rear brakes?Either manual on the drum or pump your emer brake up and down until the rears quit clicking the adj. wheel. Also I have had problems with that 10mm length on the brake rod. I don't believe that is an absolute. I have had to adj more than that. Too short =not enough push Too long = brakes lock/drag due to rod pushing in on the master cyl.

[JetDoc]

Hey Daniel thanks for the reply! To answer some of your questions.... I did adjust the rear brakes when i replaced the wheel cylinders and shoes, i checked the brake booster and check valve, the booster was bad so i replaced it, the check valve was good so i replaced both hoses (manifold to check valve and check valve to booster) there seems to be good vacuum and no leaks, I have not adjusted the B.B. rod so i guess thats next! I did however purchase a Matco Quick Draw brake bleeding kit p/n BBK70855 if anyone is intrested it looks like it will work really good, and the kit has an automatic refiller that attaches to the reservoir! I will let everyone know how it works! I apologize if i sounded like a jerk with my spring and ball comment, this thing is just driving me nuts! The car is all stock except for the stereo and tinted windows, it runs awesome i just cant get it to stop!!!

[Bleach]

That is not the correct way to bench bleed your master cylinder. That could be the whole problem.

The term bench bleed means to bleed the master cylinder out of the car, on a work bench. Usually in a vice.

You have to use a rod or dowel to push the pistons in all the way. Run the lines from the side bleeder screws as you were doing. The difference is that the brake pedal does not have enough travel to push all the way to the end of the cylinder and therefore always leaves air trapped inside. Manually pressing a dowel into it will squeeze all the air out. Once that is done then you can properly bleed the rest of the brakes. Try not to let any air into the bottom when you re-attach the brake lines to the master cylinder.

:cheeky:

[JetDoc]

Ok i'm back after this brake problem! After reading several posts and responses to my questions i'm back on the hunt for a solution! First off i checked the pushrod measurement on the brake booster and found it incorrect (adjusted too short) I corrected that issue! Then i went to the brake lines to make sure there were no obstructions (i changed all the flex hoses) all lines were clear! I again removed and disassembled the prop. valve, it was still clean and appears to be ok (but i really dont know), my last step was the master cylinder... i recieved it with the car and it was supposed to be new, well i removed it dissembled it and found out it wasent so new!! Off to the parts house i went to buy a new one, I bench bled it correctly (this time) reinstalled it, tried my new bleeded but my compressor took a crap so i bled the old way and STILL have no pedal feel with engine running! I'm ready to sell the car!

[gundee]

JetDoc

I was reading your earlier post and you said your rod length was right on. I am sure it probably was because they do not move out of adj. by themselves.

Never the less, the telltale sign of the a booster reaction disc problem is that you lose your pedal when the engine is running.

Go to Search and type in "reaction disc". You will find what you need to do. It has happened to a lot of us.

[JetDoc]

Hey greyghost

I also red the post on the reaction disk but i'm pretty sure mine is in place (i just put on a new booster) i felt the rod when i adjusted it and it dosent flop around it will come out but i can carefully reinsert it into what i believe is the reaction disk. But thanks for the reply!

[Bambikiller240]

DId you install a "new" brake booster, or a "different" (used) brake booster? Did you install the vacuum check valve oriented in the proper direction?

[JetDoc]

I installed a new booster and i believe the check valve is in the correct direction but i never did see an arrow!