More on brakes

18 years ago

The advice in an earlier post mentioned bench bleeding the master cylinder. Will it eventually be bled if the wheels are bled enough or will the air stay in there forever? I had to drain the system down on a pick-up last year. Bled the wheels, but didn't bleed the MC. The brakes have felt spongy to me ever since. Could there still be air trapped in the MC? If so, can it be bled out through the wheel bleed screws in some way?

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Comments (5)

gary__
18 years ago
If it's just a typical old school system, you should be able to bleed at the wheel, but if you started out with a lot of air in the master cylinder, it would just take a long time using the two person method.

I haven't used the gizmo's mentioned in the link, but people who have seem to like them. Use them as a tool or leave them in. They're mostly for guys who race and may push the brakes hard enough to boil the brake fluid. Allows for quick bleeding at the track. I think NAPA sells them too.

I use a cheep pressure bleeder like this one. http://www.bimmerworld.com/html/pressure-bleeder.htm It works ok. With no diaphragm to keep air and fluid separate, it's important not to store fluid in it or it will draw moisture is all.

If you're having trouble bleeding it, you might be ahead just taking it to a shop and let them do it. Don't know what they'd charge but I wouldn't think it would be to outrageous. If your vehicle has ABS and you have air in the controller, a shop might have to do it anyway. Got to get the controller to cycle some how to bleed that part of the system. I don't know how to do that, so I don't know if it can be done at home without special equipment.

Here is a link that might be useful: speedbleeder
coolvt
Original Author
18 years ago
I think this truck has ABS in the rear, but not sure. I have a lift so it's not a huge problem. I think I should try bleeding them again.
I've been looking at the pressure bleeder that you referred to. It would fit the old Volvo that I have, but not sure about the other vehicles. They mention something about a "universal" bleeder. Do you know what this is? Is it something that would adapt this tool to other vehicles?

On the speed bleeder.... I called the manufacuting tech people once. The ad was similar to the one you directed me to. It says, "Makes brake bleeding truly a one person job." It then goes on to say to pump the brakes until no more bubbles are present.
I asked the tech guy how I was supposed to watch for bubbles while I was pumping the brakes. He said, "Well you need 2 people for that part" :-) Hmm, guess it only takes one person to refill the resevoir:-)
If you know of a way to adapt that bleeder to cars that aren't foreign, I would love to hear about it.
Thanks for answering.
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gary__
18 years ago
Mine came with a large rectangular adapter that would fit the old style master cylinders, and a couple different round type adapters. All the same idea. Pick the one large enough to fit over the reservoir, clamp it down tight with chain, j-hooks and wing nuts provided. Definitely a light duty deal, but works ok.
coolvt
Original Author
18 years ago
Thanks a lot Gary, I will look into it.
Mark
john_
18 years ago
Not sure about ABS, but on a standard system you can crack the flare nuts at the M/C while pressure is applied to the brake pedal, if there is air trapped at the output ports of the M/C you can bleed it this way. In theory you would think you could eventaully work the air out at the wheels, but it may be possible to have air trapped in the M/C that sits there. I have wedged a piece of wood betwen the brake pedal and drivers seat after pumping the pedal to build pressure to make it a one man operation, much better if you have a helper though.

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