HELP Brake pedal goes to floor slowly
- Thread starter 2fpower
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2fpower
SILVER Star
- Thread starter
- #64
holy F'n sausage......
plugged the rear circuit, so only working on front, put on new front right caliper, bled. no change.
put a stack of shims between booster and master no change.
put on new master and measured carefully the distance on the master needed to the booster pin and set it. seemed better.
put rear circuit back in and bled it out again. back to the same old crap. I did not bench bleed this master, figured the pressure bleeder would do it, so might take it apart and try that.
plugged the rear circuit, so only working on front, put on new front right caliper, bled. no change.
put a stack of shims between booster and master no change.
put on new master and measured carefully the distance on the master needed to the booster pin and set it. seemed better.
put rear circuit back in and bled it out again. back to the same old crap. I did not bench bleed this master, figured the pressure bleeder would do it, so might take it apart and try that.
thatcabledude
GOLD Star
OMG
2fpower
SILVER Star
- Thread starter
- #66
well, we finally have success..... Just before I gave up.... really, I said that I was putting the wheels on no matter the outcome.
Since the last post at lunchtime, I did a sort of bench bleed of the new cardone master, no change.
popped on a used 80 master, no change.
Recall that the ABS/LSPV delete gives you two line running from the front to rear of the car. I swapped over to the other line that is actually more direct to the rear. Had to put in a union, but oh well..... bled it out and no change. AT that point, I called the wife out and did a old fashioned pumping the brakes bleed while we also had the power bleed going. This actually helped some, but still they sank to the floor.
At that point, I only had one last ditch option to pull a master/booster from my parts car. Really did not want to do that, but had nothing else that I could think of to do.
Was very careful to pull off the lines and plug them so the master never ran dry. I also did not separate the master from the booster.
Put it in and noticed another line was crimped a little going from master to the T for teh front, so made a new hard line for that.
power bled them out twice, still was not that great.
Had the wife out and did the power bleed and pumping bleed and the brakes became really hard.
Plopped the wheels on and went wheeling on my little course next door, and it did really really good.
Thank you all for your time trying to diagnose this whole mess. I figure I have about 20 hours in this.... CRAZY... I have rebuilt motors in less time.
Since the last post at lunchtime, I did a sort of bench bleed of the new cardone master, no change.
popped on a used 80 master, no change.
Recall that the ABS/LSPV delete gives you two line running from the front to rear of the car. I swapped over to the other line that is actually more direct to the rear. Had to put in a union, but oh well..... bled it out and no change. AT that point, I called the wife out and did a old fashioned pumping the brakes bleed while we also had the power bleed going. This actually helped some, but still they sank to the floor.
At that point, I only had one last ditch option to pull a master/booster from my parts car. Really did not want to do that, but had nothing else that I could think of to do.
Was very careful to pull off the lines and plug them so the master never ran dry. I also did not separate the master from the booster.
Put it in and noticed another line was crimped a little going from master to the T for teh front, so made a new hard line for that.
power bled them out twice, still was not that great.
Had the wife out and did the power bleed and pumping bleed and the brakes became really hard.
Plopped the wheels on and went wheeling on my little course next door, and it did really really good.
Thank you all for your time trying to diagnose this whole mess. I figure I have about 20 hours in this.... CRAZY... I have rebuilt motors in less time.
2fpower
SILVER Star
- Thread starter
- #69
Honestly, I don't know either. The brakes felt the same after power bleeding with the final master/booster combo. It was not until my wife came out and we did power bleeding with old fashioned pump bleeding that it suddenly became better.
After much reflection..... I think it was either my wife's magic touch... or the power bleeder and regular bleeding pumping the brakes that was the final answer.
I talked to @kc_chevota yesterday, and that is exactly how he bleeds his brakes now, so that might be the answer.
alia176
SILVER Star
Sorry for this question but I'd like a little more clarification. I have a Motive power bleeder as well and from what I understand, here's the trick: pressurize the system with the power bleeder, then use a second person to pump the brake pedal three times and hold. Then open up the caliper nipple to purge any air left the system. I assume you followed the FSM's sequence of brake bleeding procedure.
Is all this what you did?
alia176
SILVER Star
Exactly. I pressurized to about 17lbs on the bleeder and started in rear pass side, rear driver, front pass, front driver. I typically call it a bleeder valve on the caliper, but I like how you snuck in the word "nipple".
He said "nipple" - in Beavus and Butthead voice!
Thanks for confirming dude!
Tip for the kind of pressure bleeder that mounts to the MC. Dont put too much fluid in the canister as when you are done you will be left with two options. Disconnect and spill fluid everywhere or bleed until the canister is empty.
I certainly got some more bubbles out. But still my pedal touches the floor. 
2fpower
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- Thread starter
- #77
I have been replacing my master with the t100, larger bore. If you did the abs delete, we have had to do this to all those rigs for some reason.
ADVICS BMT139 sometimes hard to find, but solved our issues.
Seiken 650-71450 is the booster that might be OEM -- might not. the arguement goes on...... but it seems to work great and look identical.
ADVICS BMT139 sometimes hard to find, but solved our issues.
Seiken 650-71450 is the booster that might be OEM -- might not. the arguement goes on...... but it seems to work great and look identical.
I have replaced the vacuum boost with a remanufactured one. That was what started me down this road was a bad vacuum boost.
I have replaced the master cylinder. I tested both by plugging the two out lines for the master cylinder and there was no movement, so I think that should test for leaks around the vacuum boost and master cylinder.
I have thought about the larger bore master cylinder. I saw this larger bore master cylinder on yotamasters: OEM Advics FJ80 1" Bore Brake Master Cylinder - Yotamasters - https://www.yotamasters.com/shop/brakes/fj80-1-bore-brake-master-cylinder/
I just added the BMT-139 yesterday. Feels good so far on my test runs dialing things in. Got it from Rockauto for around $80.
What model Motive bleeder you have? Hoping to save some headaches getting the correct one the first time.Exactly. I pressurized to about 17lbs on the bleeder and started in rear pass side, rear driver, front pass, front driver. I typically call it a bleeder valve on the caliper, but I like how you snuck in the word "nipple".
