I am going to flush my brakes and use a vacuum pump to bleed the brakes. I have had problems getting a constant flow through the tube. I wonder if should try pumping the brakes some to get more fluid pressure...?? I am going to try taping the bleed screws to see if this makes any difference.
I use the MityVac etc. pump for brake bleeding. I always get a great, seemingly airless, steady stream with the front bleeder screws; not nearly so much with the rears, which are a different design. The MityVac adapters do not fit very well on the rear bleeder valves.
I keep meaning to get the right size "speed bleeders" and put these on the rears. See
" snipped-for-privacy@yahoo.com" wrote in news: snipped-for-privacy@s34g2000cwa.googlegroups.com:
Please define "constant flow". If you mean you have bubbles no matter how much fluid you move, then air is getting in past the bleeder screw threads. Remove bleed screws, wrap with some plumber's Teflon tape, reinstall, then try bleeding again.
However, in the above case, the air won't make any difference. Run fluid through until it's a clear, light straw color, and you're done. If you still have a mushy pedal, you have trapped air in the calipers, something that's very common for rear calipers with integral parking brake, and you need to use a slightly different technique..
Here's what I do.... I have some small diameter tubing. It's a tight stretch over the bleeders. I then use one of the cone adapters to go to the larger size tubing that attaches to the pump. This solved all the problems of air getting in at the bleeder. A lot less pumping since the vacume pulls nothing but brake fluid.
If you are seeing air bubbles in your hose while applying vacuum, I would not worry about it. As long as you are moving fluid with vacuum, the air is being introduced at the bleeder screw and will not have any effect on the fluid "inside" the caliper. I've used vacuum bleeders for years, and the only thing that you need to do is allow the system to "gravity" bleed for a bit after you remove the vacuum source. Oh, and keep an eye on the fluid in the brake master cylinder (level).
What year and model? Remember different makes and models have different bleeding procedures and wheel bleeding sequence. Some have safety and proportioning valves that shut off different wheels if the other wheel loses pressure or even some have anti skid where if the rear end brakes is raised up the rear wheel brakes shuts off.
Yes regular bleeding procedure. Start at wheel farthest from master cylinder. This one does have a load sensing proportioning valve [LSPV] and a bypass valve that can also be bleed. I would suggest having all 4 wheels on the ground for bleeding . The load sensing valve can shut pressure off to rear if the truck is raised up. Also if you can get the front end up higher on a hump/incline and leave master cylinder cap off aids in gravity bleeding/vacuum pump bleeding. Good luck
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