Hi guys,
I have an issue with my brakes that I've been at all day today. 1965 single circuit system.
I renewed both the rear wheel cylinders as the driver side cylinder has been leaking for a little while. The fronts were changed last year and still going strong. The car pulled up as usual, with no noticeable change in braking. I drive the car everyday for work and general running around.
Anyway, after refitting everything, I tried to bleed the brakes, and I keep getting air out of the rears and the fronts. All wheel cylinders are pumping out fluid, but with lots of air, and the pedal goes to the floor, with no back pressure. I've gone through one and a half bottle of brake fluid, but no end in sight for bleeding the brakes.
The brakes are bled in the sequence of passenger rear, driver rear, passenger front the driver front. Reservoir is always topped up, but not run dry.
I have been using the one man bleeding brake tool for a number of years, and this has worked very well for me, giving me solid brakes every time, up until today.
The lines are not blocked, as fluid is getting to all cylinders. Is there a possibility that the master cylinder could have an internal leak? There is no sign of leakage at the master cylinder unions, or the line from the master cylinder to the reservoir.
I'm at a loss as to why the simple task of brake bleeding could go so wrong after changing the rear wheel cylinders.
Any help with suggestions would be greatly appreciated.
Cheers
If it ain't broke, fix it till it is!
do u have the little washer under the fluid inlet hoses rubber it got a elongated hole in the center
was it in the old cyclinder its not numbered
did u bleed the master cyclinder first b4 trying to do the wheel cyclinders
http://www.wolfsburgwest.com/wolfsburg_new/brakes/bug_brake/bug_brakes.cfmAfter that much fluid, I'd bet master is rs.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
Dave, I don't know about the washer under the fluid inlet hoses. In the wheel cylinder, it's just the metal line to the cylinder in the rear wheel. I didn't bleed the master cylinder before trying to do the wheel cylinders. Never have in the past, and never had a problem.
Matt, I'm preparing for the worst and thinking it's the master cylinder also. I have a new one, so I might try that tonight and see how I go. Otherwise I'm at a loss. Never had a problem with any brakes before
If it ain't broke, fix it till it is!
Often during the bleeding, an old master can go south due to the piston traveling to the bottom of the bore where it doesn't usually go, and can have junk or pitting in the bore which then damages the piston cups. Good practise to do wheels and master all together.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
matberry wrote:After that much fluid, I'd bet master is rs.
x2 Les
Matt, I take my hat off to you. You confirmed my suspicion/fear. I changed the master, as I had a new one on hand. After some sweet talking the thing, and lifting the fuel tank up to get at the inboard union on the master, I changed it, and from the first pump I knew it was going to work. About 1/2 a bottle of fluid and I was done.
Just for info, when I got the master cylinder out, it was wet with fluid inside the boot where the brake pedal pushrod goes into the piston in the master cylinder.
I've just come back from a 14 mile trip to road test the car (perfect road conditions, as there's no one else on the road after midnight), and the brakes are as solid as a rock, and pull up very quick. Not bad for a set of drums.
Thanks to you and those that replied.
Cheers,
Norman
If it ain't broke, fix it till it is!
Good news Norman...
Drum Brakes are Good if kept adjusted...
its only water usually that lets drums down.. [no brakes]
Beetles in the USA never ever had disc brakes...
not even in 1978....
LEE
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---
G'day Lee,
I don't at all have a problem with drum brakes. They have been quite good, and I do keep up the maintenance/adjustments on them. Just had me stumped when I was changing the leaky wheel cylinder why the master decided to pack it in. Must have been on the way out and decided to call it quits when it did. I guess that's a good omen instead of it packing it in down the track when I needed braking.
That's it from me for the moment. I'm off to bed after a very long day on the brakes.
Cheers to all.
Norman
If it ain't broke, fix it till it is!
"" it was wet with fluid inside the boot where the brake pedal pushrod goes into the piston ""
thatst he first thing you should have looked at
yes as per above if your doing the brakes change all in one go for a good job Master and wheel cyclinder
Also you should do the 4 rubber hoses as well then you wont be touching them fora long time
the washer on the inlet side acts as a non return valve
Hi
In all my time working on VWs I've never had to bench bleed a master cylinder.
One no no that I often see people do is crimp the rubber brake lines to stop flow, this will rupture hose and will in time cause a failure in hose.
It might be too late now but its pretty straight forward to bolt on a dual circuit master cylinder, the benefits in safety speak for themselves.
Steve
Hi Steve.
OK...
when they say bench bleed a master cylinder...
How do You get it back onto the car full of fluid???
and knowing what brake fluid feels like with My fingers...lol
YIKES... I would never try that...
I hate the stuff...
LEE
1303Steve wrote:Hi
In all my time working on VWs I've never had to bench bleed a master cylinder.
One no no that I often see people do is crimp the rubber brake lines to stop flow, this will rupture hose and will in time cause a failure in hose.
It might be too late now but its pretty straight forward to bolt on a dual circuit master cylinder, the benefits in safety speak for themselves.
Steve
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---
I hear about bench bleeding, but have never done it, as the cylinders can be bled just as well when fitted.
You would still have to bleed the system even if bench-bled. I think people believe they won't use as much fluid if it is bench-bled.
As for the brake fluid on my hands. I can still smell it now.
"it was wet with fluid inside the boot where the brake pedal pushrod goes into the piston" "thatst he first thing you should have looked at"
Dave, this wasn't noticed until the master cylinder was out. Hard to see with the master cylinder still in and attached to the brake pedal and the boot covering it. As I said it was wet. More of a weep than a running leak.
Most important thing is that the job is done and problem resolved with help from those here.
If it ain't broke, fix it till it is!
I would still change the 4 rubber flex hoses as well then its good for ages
