Bleeding Brakes

duke · #1 (**permalink**) 08-13-2007, 11:52 AM

After the first test ride I was not happy with the soft spongy brake pedal. I got the wife out to the garage and after a lot of break pedal pumping and bleeding it still felt spongy. Purchased a low cost ($17) vacuum pump, a few pumps on each bleeder and the brakes were solid. Fast and good results.

Murphy · #2 (**permalink**) 08-13-2007, 01:39 PM

What many people do not realize is that the old fashioned pump bleading method can damage a new master cylinder. A pressure bleeder is money well spent.

priobe · #3 (**permalink**) 08-13-2007, 02:40 PM

Duke ,

Which system did you buy?

65cobra1 · #4 (**permalink**) 08-13-2007, 02:45 PM

I've been trying to get my brakes more solid therefore,

I'm curious about two things...
How does the old fashioned bleeding damage a new master cylinder...

What is a good vacuum system to buy?
Ivan

Clois Harlan · #5 (**permalink**) 08-13-2007, 02:53 PM

I use a mini-vac and the cost is about $25.00. I don't know how the old fashioned way can damage your MC if you bench bleed your MC first. I also have a pressure bleeder I use on my Hyd T/O Bearing that is a life saver. I pressure up my system to about 5 or 7 pounds and then pump the clutch a few times and bleed off the air. Works well for me.

Clois

Murphy · #6 (**permalink**) 08-13-2007, 04:04 PM

Clois is right you must bench bleed a mc first which many do not. The damage can occur by pushing the piston too far into the cylinder. Many MC's are not polished inside the bore past the point of natural extention of the piston. Many have a ridge inside. When you pump bleed you typically depress the pedal to the floor. The o-rings can become scraped and allow fluid to pass. This too will cause a sinking pedal.

lnfletcher · #7 (**permalink**) 08-16-2007, 08:54 AM

The trick on mine was to remove the rear calipers and tilt the bleeder more towards straight up. I had air trapped in mine until I did this. Put a block between the pads to space it like the rotor.

kayser66 · #8 (**permalink**) 08-28-2007, 08:11 PM

I too have some issues with the brakes. When I got my car running a few weeks ago I felt the brakes were too spongy. I used a vacuum bleeder and had trouble at first until I removed the bleeder valves, cleaned them and wrapped the threads with teflon tape. I can't see any air coming out, but the pedal still sinks nearly to the floor. If you pump it a few times it will stay fairly solid, but, if you try it again after a few minutes you have to pump it again. I got the car as a turn key minus from B&B so I don't know if they bench bleed the master or not. I don't have any recent experience with manual brakes, is this need to pump normal? Seems to me the pedal should stay fairly firm all the time. Any suggestions?

The manual for the pump says to start with the wheel closest to the master. I always thought you started with the wheel furthest away.

duke · #9 (**permalink**) 08-29-2007, 08:52 PM

Once you bleed the brakes and get a firm pedal it should stay that way. It should not go soft over time. Make sure you do not have any leaks. The master cylinder must be bleed down. If you have a vacum pump hook up a temp line to each master cylinder port and pull a vacumm. You need to pull down the farthest wheel cylinder first and work you way to the wheel nearest to the master cylinder. Hope this helps.: