Ongoing brake saga.....

[70Custom10Nut]

OK, I did all the adjusting and took it out for a test. The truck stops but there seems to be no power assist. When I was bench bleeding the MC I couldn't seem to get the front res to draw fluid. Is this right or did I get a bad replacement? also the pedal is real stiff with hardly any travel. Now everything in the system is new, and in theory it should work. Any insight?

[Hottrucks]

sounds like a low vacum issue...feel the peddle in your DD ( if it has power) with out it running after the second or 3rd press you'll have an Idea of what a no vacum PG feels like

[Smallz72project]

I concure, sounds like you have an issue in your booster whether it be low vacuum, or just plain bad. Typically if you have a bad MC off the gecko the pedal will just go to the floor or slowly sink (bleed off). Do you have a pretty radical cam in your engine? Perhaps everything is fine and you just arent pulling enough, which in that case you'll have to add a vacuum pump, settle into manual brakes, or swap out your cam.

[70Custom10Nut]

I'm running the same setup as always. (no serious cam ) since I got it out of storage I've replaced the entire brake system, MC, booster and all. Now, I have the vacume line going to a fitting on my manifold. Again, I ran this set up before with no problems, and that is what has me confused, In the morning I am going to check to see how much vacume I do have at the hose.

[72lb4x4]

I got tired of messing with mine and took it to a locally owned shop and had them bleed it after I replaced the parts.

I kept emptying the MC and having to start over.

[hayhauler71]

If you have a check valve in your booster hose make sure it is flowing the right way or is not defective.

[cdowns]

do you have a factory service manual to read how to properly bleed the brake system? and to properly do the brake system work?

[CCCC]

Based on your description, you may have two problems - so - one at a time. With hard pedal and such effort, it sounds like the booster is not working. If you have good vac to the can, and if the check valve is working properly, either there is a linkage problem (too short) and the booster/diaphragm is not being engaged by the pedal action or there is an internal leak and the diaphragm action is kaput.

Once the booster action is good, try bleeding both front and back sides of the MC while installed - one side at a time. Open the connection a bit at the MC or the prop valve and have someone push the pedal SLOWLY while you look for air/fluid and retighten the connection before they let the pedal up. Leave the top off the MC so you can see any bubbles or turbulence that may occur in there - good way to see if the piston action seems normal. Pedal must be pushed slowly or you will have fluid out the top and on some paint. Keep us posted.

[Hottrucks]

good call on the linkage being to long if the MC can't fully disinguage the peddle so that it can take in more fluid ..it will give a hard peddle issue..

one way to bleed is to put a piece of vacum hose on your bleeder and put it in a jar so the other end will be in some fluid..open bleeder slowly push your peddle a coulpe times and then refill the MC and repeat...this is a good way to flush your break fluid and keep it air free

[70Custom10Nut]

Fixed. It was a bad MC. Is there more than one way to mount the booster bracket? I had someone tell me that I needed to mount mine the opposite to how I have it. so that the MC will sit perfectly level? I know that I put it in correctly, and that I got it out of another 70, besides none of the levers or push rods will line up if I did that. Right?

[Hottrucks]

pic??