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Brake Bleeding...

2.2K views 8 replies 7 participants last post by  Bihili  
#1 ·
I am sure this will go down as another "dumb" mistake on my part, but... I was bleeding my new brake system - front disks (CPP), rebuilt rear, and new master cylinder and booster brakes (CPP) - with a friend and we could not get any fluid to circulate. Seemed like it would not even leave the MC! Yes, we started with the furthest line and opened the valve. Nothing. Any suggestions? I appreciate the thoughts in advance...
 
#3 ·
First question, you did bench bleed the master cylinder before installing? Which master cylinder? A friend had much the same problem and it was a bad master cylinder.
Terry
 
#5 ·
The last time I changed a bunch of components in the brake system, I was pulling my hair out, trying to get the system to bleed.....I ended-up having to use a home-made brake bleeder that Acardon told us about.

"I made my own pressure bleeder and it worked great. I tried a Miti-vac and it kept pulling air bubbles from around the bleeder valve threads, so I never knew when all the air was out of the system. I used a steel plate a little bigger than the top of the M/C. Drilled and threaded for a 1/4" pipe. Used a air line fitting to accept the air hose and a piece of rubber to seal it to the top of the M/C and clamp the plate to the M/C with a C-clamp. Set the regulator to 10 or 20 psi and your set to bleed. Cut a air passage in the rubber gasket, between the reserviors, to get air to both reservoirs....Bleed the car as you normally would.....Going from left rear, to right rear, then right front, and finally left front.....Check the fluid level in the master cylinder constantly and keep it full.

The store bought units pump fluid into the reservoir to keep them full, but if your careful with the amount that you bleed out, you can keep the reservoirs full."

Image
 
#7 ·
I admit it, I did not bleed the mc as I did not have a kit. Thought that It would just take a little more time. I do have the pin inserted into the mc. That would suc$ if it were bad as I got it months ago from danchuck and we know they are sooo supportive after 30 days! Zbad55, do you have any guidance in how to set the correct length? Thanks everyone.
 
#8 ·
The brake pedal pushrods should be set so it's not binding and not pulling the pedal itself. The clevis pin should be able to be pushed in without moving the rod. Check to make sure the clevis can rattle a bit and is not tight. As for the push rod in the booster some are pre-set, but you want about a1/32“ clearance from the end of the rod to the cup in the m/c as you don't want any preloaded on the m/c.

They way I checked mine was to put a small dab of toothpaste on the tip of the rod and then put the m/c on the booster, then pulled it back off and look to see if any of the paste transfered to the cup of the piston in the m/c. Now my booster had an adjustable booster push rod so I could make adjustments as needed. Now this was my DIY method, but they do sell a tool to check the booster pushrod length. Good luck and after you bench bleed the m/c you should be able to get the system bled.