Just replaced a rear caliper this past weekend and "accidently" let the master cylinder run low/out of fluid. Attempted to bleed all four calipers and LSPV valve but still have to push the brake pedal all the way to the floor to stop. When bleeding the lines I was never able to develop much pressure or volume of brake fluid from any of the bleeder valves. Is there something that I'm missing in the brake bleeding process or a way for me to confirm the function of the master cylinder?????
96LC Brakes,bleeding&master cyl?
- Thread starter utlandc
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Others may have input, but you likely have a LOT of air in the system and will simply have to run a bunch of fluid through to get rid of it. Bleed in the reverse order to get rid of air in the MC unless you've already pulled it through all four calipers. In other words, bleed the LF caliper to get air out of the MC - no sense pulling it through all 4 calipers/lines.
Worst case is you'll have to pull the MC and bench bleed it. If you have clogged bleeders and can't get volume through then you should replace them. Also, a bleeder kit that uses a pump to PULL fluid at higher speeds may be in your future if you continue to have trouble getting the air out.
DougM
Worst case is you'll have to pull the MC and bench bleed it. If you have clogged bleeders and can't get volume through then you should replace them. Also, a bleeder kit that uses a pump to PULL fluid at higher speeds may be in your future if you continue to have trouble getting the air out.
DougM
utlandc said:
I have had good success by opening the bleeder for a couple of pedal pushes, then closing it and slowly pushing the pedal down once and repeating over and over. This seems to push the air out faster. Doug is right, you are just going to have to bleed until all the air is out.
Jim
Like it or not, a hand pump would be the best way to bleed your lines. I just replaced all my fluid with synthetic stuff over the weekend and the hand pump (MityVac) made it a breeze (especially since I had my 14yr old do all the pumping 
). For all four lines, it appears I used about 3/4ths of the 32oz bottle.
After I was done, it took about 3 pumps of the brake pedal for it to get hard near the top of the stroke. When driving, the pedal goes down about half to 3/4ths of the way but nowhere even close to the floor.
Sears sells just he basic kit for about $35. I got the 'deluxe' kit for $50 a few years ago which now sells for $70. Good luck.
WET
). For all four lines, it appears I used about 3/4ths of the 32oz bottle.After I was done, it took about 3 pumps of the brake pedal for it to get hard near the top of the stroke. When driving, the pedal goes down about half to 3/4ths of the way but nowhere even close to the floor.
Sears sells just he basic kit for about $35. I got the 'deluxe' kit for $50 a few years ago which now sells for $70. Good luck.
WET
Jim_Chow
V8_Fan
IdahoDoug said:
You don't really have to pull the MC to bench bleed. IMHO, it's easier to do on the car. Leave it bolted up, but remove the hard lines. I used the cut off male ends (2) from an old hard line (use a hard line cutter to cut so the tube doesn't get squashed; you can alwasy buy the short hard line piece that connects to the front most port of the MC for about $5 from your dealer). Screw these into the outputs of the MC, then stick 3/16" i.d. (IIRC) pvc tubing over the cut end, then feed the tubes back into the MC. This way, you just fill up the MC w/ fluid, then press on the brake pedal repeatedly unti all bubbles disappear. This also saves you from having to transport a MC whose resevoir is full of fluid and risk spilling it all over the paint.
- Thread starter
- #7
Thanks for all of the input. I ended up getting the Sears vacuum pump (not the most efficient process but seem to do an ok job), dedicating a whole evening and probably close to 55 oz. of brake fluid to complete the job and the brakes work better than I think I can ever remember them working in the past (although just about anything was going to be a vast improvment from where I was). I did have someone pump the brakes at the end to complete the process at each bleeder valve.
Jim_Chow
V8_Fan
Wileetoyote,
I have the Mityvac metal bleeder pump unit, but could never get the thing to work correctly. It seems it doesn't seal at the bleeder nipple well (sucks in more air than fluid), so I usually use a piece of 1/4" i.d. pvc tubing and have my wife pump the pedal and fill the master resevoir while I work the bleeder valve.
I have the Mityvac metal bleeder pump unit, but could never get the thing to work correctly. It seems it doesn't seal at the bleeder nipple well (sucks in more air than fluid), so I usually use a piece of 1/4" i.d. pvc tubing and have my wife pump the pedal and fill the master resevoir while I work the bleeder valve.
Well I just did my brakes and this time I bought some speed bleeders, can't say enough how much better they are than the old 2 man pump and crack system. I got 5, one for the LSV and attached some hose and drained each into separate cans. I could bled all 5 at once, only thing I had to do was pump and keep the tank full of fluid. Man and the rear lines pumped out some black stuff, I went through 4 bottles of valvoline synthetic before I called it good.
4 Bottles? 
small bottles or the bigger 32 oz'r?
This brings up a good question...whats the overall capacity of the brake line system? Meaning, all brake lines, each caliper, and master cylinder.
Any one brave enough to hand pump their system dry and measure it for us
come on' take one for the team.
btw Jim, your right about the tube the MV uses. It does suck (literally). My kit has a bunch of little fittings to get around this but is more trouble than its worth. Thats why I had my 14 yr old son build up his forearms like Popeye whilst I sqeezed down on the tube around the fitting.
small bottles or the bigger 32 oz'r?
This brings up a good question...whats the overall capacity of the brake line system? Meaning, all brake lines, each caliper, and master cylinder.
Any one brave enough to hand pump their system dry and measure it for us
come on' take one for the team.
btw Jim, your right about the tube the MV uses. It does suck (literally). My kit has a bunch of little fittings to get around this but is more trouble than its worth. Thats why I had my 14 yr old son build up his forearms like Popeye whilst I sqeezed down on the tube around the fitting.
