Brake bleed - neverending?

Kernal

 
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Dec 10, 2007
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That's the one man bleeder bottle; it looks almost too cheap to work but it does. Only thing is the bottle is small so you have to empty it at least once for each bleed screw if you have a lot of air in the system.
 
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A old tech I worked with made his own with a glass jar and some tubing. He would pump till no more air came out then I'd help him with the two man method. Always worked.
 

jvazquez53

El Tractor
 
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That's the one man bleeder bottle; it looks almost too cheap to work but it does. Only thing is the bottle is small so you have to empty it at least once for each bleed screw if you have a lot of air in the system.
Yep, small but does the job. When I went to buy it the salesperson wanted me to buy the vacuum pump type. He tried to steer me away from the little bottle, but for what i needed it, worked fine. Drawback; have to empty the bottle a lot! There's a thread on the 60 forum on how to make one with a glass jar and some tubing.:cheers:
 

redeye

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Ok, here's the latest. Did another cycle and got all air bubbles out of all calipers. I ended at the LSPV. We could not get air bubbles to stop coming out of the valve. A rapid succession of bleeding would minimize the air bubbles, but if we took a break (my wife was getting tired) and did it again, tons of air would come out - sudsy almost.

I "cracked" the fittings at the master cylinder, but no air bubbles came out when pressing pedal down. Just nice clean non-bubble fluid.

I did replace the LSPV with a used one from a reputable vendor here on MUD. There are NO leaks coming from anywhere.

Here's my suspicions, but again, I am not a professional mechanic. Just a shadetree :banana: at best. :)
- bad LSPV
- bad line coming from front, ending at LSPV (one of two, or both - the fittings were pretty well rusted. We had to use vice grips to remove from old valve and reinstall on my new-to-me LSPV).
- master cylinder? Was good before axle swap though. :meh:

If it's recommended to replace the lines that run from the front along the frame all the way to the LSPV I'm totally fine with that - although I can't see any reasonable way of installing them with kinking them. Those things are LONG and bendy.

At the very least I've cycled a massive amount of nice, clean fluid throughout the system. :D
 

Pin_Head

 
 
 
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If you are still having trouble getting a pedal after all that bleeding then maybe the master is bad. Have someone pump the brakes while you peek inside the reservoir and look for turbulence. If there is turbulence every time they step on the brake, the cylinder is leaking internally and may also be sucking air back into the cylinder on the back stroke.

When I woked at a high volume shop, we exclusively used the 2 person bleeding method because it was faster than getting out a gizmo and it worked first time every time for thousands of brake jobs. If it didn't work, there either was a leak or the master was bad.
 

redeye

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Went out and checked for turbulence. Saw a very minor drop, then rebound of fluid. No bubbles.

Any chance my rear calipers could be leaking? I don't see anything coming from the (new) soft lines, (new) banjo bolts, or (new) bleeders. Maybe it's leaking inside the caliper? You'd think I'd see fluid somewhere if the piston seals were shot.
 

Pin_Head

 
 
 
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Doesn't sound like it is leaking past the piston seals. It might be sucking air on the back stroke, but this would happen only if the seal is bad. If you get a firm pedal after pumping it up and it holds without dropping, chances are the master is OK. When you bleed them you are using the MC as a pump and closing the bleeder valve makes it go one way. If you do it the way I described and close the bleeder before the fluid stops you can't suck air back through the bleeder. You also need to squeeze that fluid out hard, as the turbulence blasts the bubbles out. Don't pump the pedal. Just one stroke at a time. If you are tired of bleeding them you could tow it to a shop and have them do it.
 

wxm

 
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Just echo what's said. If you are doing bleeding it with 2 person method. The only time that you open the valve is when your assistant acknowledged the pedal is pressed and held down, and then he/she will let go only after you close the bleeder. You only open the valve for a second or two and close it before the stream is running out. It is also very important that you don't let the reservoir run low in any time, so check/refill the reservoir after a couple of pushes.
 
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When I did the lspv and brake hoses a little while ago I had troubles getting a firm pedal doing the push the pedal method. I ended up gravity bleeding it. Cracked all 5 nipples and left it for 15 minutes, checking and toping up the master every so often.

After that I had good brakes. Not sure if there are any complications with ABS though, as my cruiser don't have it.
 
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Gravity bleed

A good friend of mine (ASE certified master tech) does what he calls a gravity bleed. He will crack the bleed valve and just let it sit open. after 10-15 minutes there should be a steady flow of fluid (make sure you have plenty in the master cylinder) and then he closes the valve, then repeats on the other 3. it actually makes a huge difference, it just takes a while longer. might be worth a shot.
 

redeye

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Today I did an in-place "bench bleed" on my master cylinder. Definitely had air trapped in it. I re-bled each caliper and there were zero air bubbles on rear calipers. DS front caliper had a small amount. LSPV appeared to be getting better but still had air bubbles after approx. 6 or 7 cycles. The pedal felt slightly better today after doing all that. Will continue to bleed more out of the LSPV tomorrow and report back.

I read somewhere on here that a guy did something like 30 cycles on the LSPV.
 

coax

 
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It took me quite a long time and probably a few gallons of fluid to properly bleed the brakes. In the end, the best solution I found was to hook up a motive power bleeder, open the bleed valve, and then stomp on the brake pedal. Slow pressure didn't seem to help with the air that was "stuck" somewhere. Really needed to get after it and create some turbulence in the lines to remove the air.
 
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Slow pressure didn't seem to help with the air that was "stuck" somewhere. Really needed to get after it and create some turbulence in the lines to remove the air.

This is a fact, any air that you miss will work its way back up the line further from the bleeder. The 2 man method properly timed and working as quickly as the two of you can keep it together will net the best results.

Do not !! lift the pedal until buddy has the bleeder tight at the end of every stroke.

If you replaced the LSPV, did you bench bleed it?

Keep a close eye on the master it is divided in two halves, front and back inside the resivior so keep it as close to the top as you can.

One more tip ........ if you replace your pads you will also purge the additional "old fliud" that is sitting/trapped in your caliper pistons (the fluid that has been added to make up for your worn pads), and may be a source of your spongy pedal. These rigs eat pads, replace them often and you will extend the life of your entire system.
 
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redeye

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Front pads only have 2,700 miles on them or so. Rears are in good shape as well.

I did indeed replace the LSPV, but did not bench bleed it. Any tips on doing this? I assume it has to be removed from the truck to do so?

I'm going to give the two-person method another full run today. A friend of mine, and a fellow Mud member, is coming over this afternoon.
 
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I would leave it in the truck and just spend a little extra time bleeding it, if the fluid is coming out bubble free your good to go.

The traditional sequence is to start on the long line (right rear) and work your way to the short one (left front) but I seem to remember the FSM had you going in the opposite order. It has been a year since I did mine and I don't remember.

I do remember how solid the pedal feels once you get it right.
I put over a quart through my system before I got it the first time i did my cruiser and more than one (more like five) full trips around my truck.
 

redeye

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Well....I found my problem. It was my fault all along. I had mounted the calipers on the wrong sides. I didn't even consider that they could be mounted on the wrong sides, upside down. Doh! :bang:

So I swapped sides, did a gravity bleed and brakes felt immediately better. Finished it off this morning with another two-person bleed and now they feel back to normal.

The upside (in addition to learning something new) is that I've got all brand new synthetic brake fluid in my lines. Yay!
 
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