No Brake PRessure on new brakes?

[Jnonni]

I am restoring a 69 GMC 2500. It has power drum brakes. I have replaced all new brake lines, wheel cylinders and the master cylinder. I have bled the brakes 2x and it holds fluid no problem, however the pedal goes to the floor. I remember when installing the Master Cylinder that it said if air got in there it could do this, but was hoping not to have to take it apart again. Ideas? Does this sound right?

[Hawghauler]

Did you make sure to adjust the shoes? Make sure they are making contact to the drums. Did you get the correct M/C for the booster? Disc and drum M/Cs aren't the same, The rod between in shorter in one. Bleeding should have made any disconnected pipes show up, so the next question is did you bench bleed the M/C before bleeding the wheel cylinders?

[hugger6933]

First off did you bench bleed the master cly before putting it on the truck? You said you have bleed the brakes are you getting just fluid when you bleed? Or nothing at all? Information is key to open the locks of knowledge[hey thats good I just came up with that] We need a little more info to help with this. Jim

[LockDoc]

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As stated above bench bleeding the master is important....

On the drum brakes, one thing I found on mine is when you put everything back together and adjust the brake shoes you can’t just adjust them out until they start rubbing and quit. You have to adjust them out as far as they will go and you cannot turn the wheel or drum at all. This centers the whole assembly in the drum. (I even tap around the drum as I tighten them to help them center themselves) Then you back them off until the wheel just turns, and stop. If you only adjust them out until they start rubbing and quit, the first time you press on the brake pedal the brake shoe assemblies will center themselves and you will have too much clearance between the shoes and the brake drum. I also put three lug nuts on backwards to hold the drum tight against the axle on the rear.

I know it is a pain in the butt to try and hold the self adjusters off of the adjuster wheel while you back them off, but this is the only way I could get my drum brake shoes adjusted correctly.

LockDoc
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[Jnonni]

I did bench bleed the mc, however i had a leak on a junction block and it list its fluid.. I redid the junction block and refilled the system w fluid. So maybe it needs to be bench bled again? I will try to adjust the pads first as i have not done that yet. I assumed they would not need to because i replaced the pads. Will let you know. Thanks.

[LockDoc]

Originally Posted by Jnonni

I did bench bleed the mc, however i had a leak on a junction block and it list its fluid.. I redid the junction block and refilled the system w fluid. So maybe it needs to be bench bled again? I will try to adjust the pads first as i have not done that yet. I assumed they would not need to because i replaced the pads. Will let you know. Thanks.

Yes, they will still need adjusted...

LockDoc