Posted by Keith in Washington [172.71.147.155] on Monday, February 13, 2023 at 18:40:34 :
In Reply to: brake bleedng posted by Jerry in Idaho [172.71.142.60] on Thursday, February 09, 2023 at 15:25:49 :
I never have had a lot of luck with vacuum bleeders. I would think the pressure ones would work better. these are the ones where you put a cap on the master cylinder and pressurize the attached fluid reservoir. This type will keep a positive pressure on the whole brake system as you bleed each brake cylinder.
The issue would be connecting the reservoir to the standard PW master cylinder. The solution is to replace their master cylinder connction with a pipe thread fitting that will fit the cap of the PW master. that should be an easy task.
The problem I have had with a vacuum bleeder is that it takes so long to get bubble free fluid coming out of the brake cylinder. The problem is two fold. I believe that with the loosened bleeder, the vacuum is sucking air through the bleeder threads and you can't really stop that. The other issue is that if you are starting with an empty brake system, the first two brake cylinder never seem to run bubble free as it seems that you are sucking air out of the other brake lines and cylinders. The vacuum system seems to work a little better if the system is already full of fluid.
The other down fall of the vacuum system is that you can run the master cylinder dry if you are not watching it closely. The pressure bleeding systems have a large reservoir of a quart or larger.
The following link is an example of a pressure bleeding system. Note that it would be very easy to make a pipe thread adaptor that will attach to the tube coming out of the fluid reservoir. It's also made in the USA which is nice.
https://www.amazon.com/Motive-Products-European-Bleeder-Pressure/dp/B0002KM5L0/ref=sr_1_14?crid=1R3UF8QEXNLN2&keywords=pressure+brake+bleeding+system&qid=1676331143&sprefix=pressure+brake+bleedo%2Caps%2C141&sr=8-14
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