bleeding the brakes again..WHY!

[claybill]

hello all...i have brake problems.....(not on my plymouth all 3 of them seem ok)..after all the discussions of power disc brake conversions i went ahead and DID IT! ..ON MY 1960 IMPALA HARDTOP.! 3 mechanics couldnt get it to work properly after hudreds of dollars!! hundreds!!! finally it does work...BUT every spring the pedal goes to the floor, and i have to take it in to bleed brakes again..repeat..(I am not doing any of this work, only professional mechanics)

I am only paying out the money...i am near the end of my cash and frustrations..

------------

change my mechanic...i did..twice

there are NO leaks in my system that i can see..no drips or wetness or puddles, at the wheels, or booster, m/c, or the lines. what is happening?

m/c is full and clean...pedal goes slam bang to the floor. i pumped 35 times and it didnt build up. stumped.

is there a hidden leak?

how is air getting into the lines?

master cyl..?? this is the second one. just to make sure.

bill

[JIPJOBXX]

First of bill I think you should make up one of those simple bleeding tools described here on one of the old treads. All it takes is a garden type sprayer , a hose and the cap that goes on your master cylinder. Then re bleed your brakes for the 45 times and get all that air out of the system. I had all kinds of problems with mine and I finally got them to work correctly by just going over and over the entire system under pressure. Now that being said I would check all your wheel cylinders to see if there is a slight leak in one of those. I know its a pain in the neck but I would start there and see if any of them are leaking past the rubber fme cover. I also would check around where the brake lines attach to the wheel cylinders. You haft to have a leak somewhere? And so I would just start at that point and do it yourself.

[claybill]

yeah jipjab...i am on to one of those pressure things..this weekend is the day to deal with this. cleared out the garage a bit and i am ready to go.!

thanks for the encouragement.

bill

[kencombs]

Maybe the needed residual valves are missing or defective. It is possible that with no residual pressure, a change of temperature could 'shrink' the fluid and draw air past the wheel cyl cups as they only seal in one direction.

[Rodney Bullock]

HI Bill, do you have a power brake system on the 60? Is it a period correct system?Usually if you have a problem like this it's the Master cly. I had this problem on the truck we changed the MS and it went away.

If there is no visible leak then air is getting into the system. The M/C must build pressure and holfd it.

I am helping all my club members and friends get their cars in order for the riding system and half the problems are brake related. It's a hard knock life.

What condition are the lines in? I have one guy here that has metal lines that are so thin that they are letting air in and there is no visible fluid leak.

Good luck as always, Rodney

[claybill]

this is an aftermarket system using new stuff from a camaro, i thnk.

power booster 8in double diaphragm.

i will try the m/c again..it is a dual chamber one. if it was defective wouldnt it be drained? all lines are new. to all 4 wheels.

bill

[55 Fargo]

Did you bench bleed the MC first?

[Rodney Bullock]

this is an aftermarket system using new stuff from a camaro, i thnk.

power booster 8in double diaphragm.

i will try the m/c again..it is a dual chamber one. if it was defective wouldnt it be drained? all lines are new. to all 4 wheels.

bill

Bill, when you are in the car, put your foot lightly on the brake pedal. Then start the car. Does the pedal rise? If it does not the booster is suspect. It should pop up when vacume is present. If not check the vacum source.

[P-12 Tommy]

yeah jipjab...i am on to one of those pressure things..this weekend is the day to deal with this. cleared out the garage a bit and i am ready to go.!

thanks for the encouragement.

bill

Bill, I'm going to second the motion on the pressure sprayer. That's the only thing that got all the air out of my brake system, and quickly.

Tom

[claybill]

i have written down all comments...we have 4in snow this am!!!$%^%&&^*&

#1 the pressure thing...there is no way to attach the pressure pump to the top of the m/c as it is vented by louvers.!! sprays fluid all over !!! i even made an adaptor of sorts..just not a good idea, spurts fluid everywhere..

#2..booster might be worth checking into...hoses to booster are tight and come off manifold . booster shows no fluid leaks/drainage , i felt inside to see if ther was any fluid insid the booster?!!! dry.

we have tried a lot of these attempts last fall and got it working ok ..then when it sits over the winter , the pedal goes wham! to the floor, with NO pressure or slowness at all. just a simple push to the floor, with motor running..no feeling of vacuum or resistance. i think this is a key to the answer..... maybe it is the booster...and i had 2 of them, and sold the spare! ##$^%

little by little, day by day,..$ by $, we move forward!

bill

ps...i have 5 cars now...i should sell at least 2...i looked at each one yesterday...I CANT BEAR TO PART WITH ANY OF THEM..ALL SO NICE!!!!

maybe next year.!

[Young Ed]

Bill I think of heard of a failure mode where the booster lets brake fluid get sucked into the engine

[Plymouthy Adams]

if I read this correctly..there is no loss of fluid..there is no build of pressure when pumped by foot...

I would look at a forward piston in the MC to be stuck in place..this would prevent the MC of building pressure..no fuild is being displaced..all you have is empty pedal movement..

[claybill]

tim...that is exactly my symptoms...new m/c on monday..

rodney...i started the car and slightly depressed the brake pedal during start-up..i could feel the brake pedal surge momentarily..the vacuum! then it goes to the floor..

i think tim's answer is ta good direction to proceed. it all points to the m/c.

i also found out that the m/c of the dual pot style comes in 2 plunger diameters..1-in. and 1-1/8 in. the 1-in gives more pressure and is the one i will be using....(i do have both m/c's )

Ed....fluid getting into te motor? how can it be sucked in? thru the vac tube? could i look inside the tube to see if there was fluid residue?

bill

btw....i took my 41 coupe street rod (lollipop) in to get stock cam and lifters istalled....anybody need a hot cam for a 360??!!!!! cheap.!

[Young Ed]

Ed....fluid getting into te motor? how can it be sucked in? thru the vac tube? could i look inside the tube to see if there was fluid residue?

.!

Thats what I've heard. But if you aren't having fluid loss then that wouldn't be your problem.

[Plymouthy Adams]

I remember Ford having quite a bit of trouble with this sucking in of fluid Ed mentions by their design...again this is a good place to search if losing fluid with no evidence of leakage at lines and cylinder seals...usually relulting form rear master seal..there is usually evidence in the foam and rubber bellow to warrant further inspection

[kencombs]

Do you have no pedal resistance at all, but bleeding fixes the problem?

Could be a stuck piston as someone mentioned and the bleeding process frees it, but my question would be: how did it get moved to the applies postion while parked? If it stuck on first application after storage, but didn't apply the brake: Then something else must be the root cause.

[claybill]

good thnking Ken...i pulled into the garage, braked and put it in park. that was in november. really tho i cant rememebr if i hit the brake after in park or not..who knows. anyway the m/c comes off tomorrow and i will checkit out....see new thread for my bench bleeding question..

bill aka claybill

[Tom Skinner]

Dear Claybill,

You have gotton really good advice already and I agree with it all.

Its either the master Cylinder or the Power Booster.

Please don't take this wrong: but I am glad you are at the end of your $$ and you are finally taking the bull by the horns and going to fix it yourself.

Unless you are "very well to do" you'll get hosed by well intentioned mechanics everytime. Its not their car so - its your problem - every penny of it.

Its kind of like "owning it" when you take ownership of it - you fix it.

The pride you feel from this, my friend, is the real deal.

Good Luck! and may the Chrysler Gods Shine upon you and give you peace. You can do this!

Get your Service Manual out and put on your Thinking Cap!

Tom Skinner

Huntersville, NC.