Hi,
I have a '68 and all was fine with the brakes before I swapped rear ends. I built a 12 bolt and installed new wheel cylinders. The font brakes were not messed with. Went to bleed the brakes and my friend would pump the pedal 3 times and with the pedal down, I'd open the bleeder until flow of air/fluid stopped, I'd close the bleeder and he'd let off the pedal. We repeated this, making sure the master cylinder did not run low.

After about 20 minutes and 2/3 a quart of fluid, the system still had a lot of air and the pedal, which had some feel upon first pump, would go to the floor until it was pumped several times.

There are no visible leaks anywhere and after going though so much fluid, I am sure I would see a puddle somewhere (I've not checked my carpet at the firewall yet though).

I don't know if it matters but I've typically only pushed the pedal to the floor one time, not three as my friend insisted.

Any ideas?

Did you let the rear compartment on the master cylinder run dry?

If you did it will always feel spongy and you should pull the master and bench bleed it.

also just to make sure were on the same page. When you bleed brakes you have your helper in the car pump the pedal 3 times or so. Then while he starts depressing the brake pedal you open the bleeder. When he gets to the bottom, he should let you know and you close it before he makes it to the bottom of the stroke. This will make it so no air enters back through the system when you bleed it.

I did have to bleed mine the other day and we did get the master cylinder compartment too low, getting air in the system.

Id try to bench bleed it again.

Matt

Did you let the rear compartment on the master cylinder run dry?
Matt
No.


Then while he starts depressing the brake pedal you open the bleeder. When he gets to the bottom, he should let you know and you close it before he makes it to the bottom of the stroke. This will make it so no air enters back through the system when you bleed it.



Matt

No. He told me to open the bleeder once he had the pedal to the floor. We'll try it your way.

Also, I have a nice power bleeder (got it from Jeggs) but it would not seal on the master cylinder so I'm doing it the old fashion way (not done it this way in years). That power bleeder is very nice (when it works :).

Thanks.

Gotcha,

Just throwing something out there. for ya to try.

Matt

Try letting them gravity bleed and see if that helps any.

Turns out, after driving it a bit, that my master cylinder is leaking fluid out of the back. Fluid runs down onto the frame and fender liner. Did not show up after 1qt of fluid when bleeding. Had to drive it first.

sounds like a refurb master and your on the road!


Matt