TR4/4A TR4 brake problem

[joejoecat]

Just replaced the master cylinder(from one of the big three),brake pads,rebuilt front calipers,SS brake lines,rear brake cylinders and shoes and changed fluid to DOT 5 silicone.The problem I am having is a low brake pedal on the first pump ,the second pump the pedal is where it should be and it holds there as long as my foot is on the brake even lightly.Take my foot off the brake for a couple of minutes and again low pedal on the first pump.I am not loosing any fluid and have bleed the brakes about three times.I'm kind of lost for where to go next.Any ideas would be appreciated.Thanks

 

[Andrew Mace]

My first thought is rear brake adjustment!

 

[TR4A_IRS]

Did you bench bleed the new MC?

 

[joejoecat]

I don't think the MC was bench bled.

 

[LBCs_since_1988]

There's still air in there. The more you pump the pedal the more you mix the air and fluid into a nice frothy broth. Sometimes you need a couple days for those microscopic bubbles to come together so you can effectively bleed the system.

 

[TR4A_IRS]

I think you have air in the system, maybe in the MC. If bleed of the brakes doesn't get rid of the soft pedal, you may need to remove the MC to bench bleed it.

BTW, you didn't get a bad MC did you? See the stickyed post above.

 

[Geo Hahn]

I think you can sorta do a bench bleed with the MC in situ by slighly opening the outlet lines an doing some pumps. Not exactly the same as a bench bleed but this is what I did in lieu of R&Iing the MC and it worked.

 

[joejoecat]

Geo,thank you,thank you,thank you. It worked !!!