Brake problem
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
Brake problem
I did the rear disc swap a couple of months ago with a dana 60. I also installed a hydroboost unit, adjustable prop. valve, and a Saginaw p/s pump.
It has been about three months since the install, with great braking the entire time. I should mention that during the install, in my haste to finish before it got too dark, by mistake I grabbed the p/s fluid and poured it into the new m/c. Yeah, I know. Anyway, next day I flushed the system and changed to another new master. No problem for three months.
Today I get in and the brake seems high. After about three miles the brakes are dragging pretty hard so I parked it. Fluid in master has a brownish tint. All the wheels spin freely, no leaks at the wheels, hoses seem fine. There was a drip at hydro/master junction, which worries me. I started it up and drove it home, and it seems fine.
Ideas???
It has been about three months since the install, with great braking the entire time. I should mention that during the install, in my haste to finish before it got too dark, by mistake I grabbed the p/s fluid and poured it into the new m/c. Yeah, I know. Anyway, next day I flushed the system and changed to another new master. No problem for three months.
Today I get in and the brake seems high. After about three miles the brakes are dragging pretty hard so I parked it. Fluid in master has a brownish tint. All the wheels spin freely, no leaks at the wheels, hoses seem fine. There was a drip at hydro/master junction, which worries me. I started it up and drove it home, and it seems fine.
Ideas???
Fleet Mechanic
Joined: Aug 2009
Posts: 1,771
Likes: 9
From: Western Washington
It sounds almost like one of the check valves (inside the master cylinder) got stuck and isn't releasing the pressure in the brake lines, do have a spare master? I say get one and swap it in and see what happens.
Sam
Sam
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
Thx. I'll keep everyone posted.
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Cargo Master
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If you swapped all the fluid out I'd bet you just got a crappy master. Swap
It out and flush your lines again.
It out and flush your lines again.
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
I finally got around to looking into the problem. I was able to get new front soft lines for $30 for the pair from Rock Auto. I love that place. Those are the lines rated for 7500 lbs and up!! At A.Zone they cost $50 for one!!
Anyway, I pulled the front calipers to throw in a seal/rebuild kit. Man, they were full of crap. I guess it had been about 6 ... 7 years since I rebuilt them. The left took some work to remove the pistons, but got them. The right side, however, was something else. One piston was completely frozen in the caliper. Tomorrow I am going to the J/Y to pull another to replace it. I have never seen one I could not remove.
Hopefully this rebuild of the front cals. will solve the problem.
I find driving with the brakes dragging/locking really effects my mpg. Imagine that.
Note** Even with the new master in, I am still getting a little fluid 'sweating' between the master and hydro. I can reach down there and wipe off a drop every time I open the hood, and that bothers me. I wonder if the hydro is the one causing the problems ... coming on by itself!!
Anyway, I pulled the front calipers to throw in a seal/rebuild kit. Man, they were full of crap. I guess it had been about 6 ... 7 years since I rebuilt them. The left took some work to remove the pistons, but got them. The right side, however, was something else. One piston was completely frozen in the caliper. Tomorrow I am going to the J/Y to pull another to replace it. I have never seen one I could not remove.
Hopefully this rebuild of the front cals. will solve the problem.
I find driving with the brakes dragging/locking really effects my mpg. Imagine that.
Note** Even with the new master in, I am still getting a little fluid 'sweating' between the master and hydro. I can reach down there and wipe off a drop every time I open the hood, and that bothers me. I wonder if the hydro is the one causing the problems ... coming on by itself!!
Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,174
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From: Near Los Angeles
Today I pulled and rebuilt the front calipers, and replaced the front soft brake lines. I installed the cals dry, and can't seem to bleed the brakes, no pressure build up, hardly any air coming out at times. Other times fluid shoots out. I bled and bled and can't build pressure.
Any thoughts? I've searched system for a leak and come up dry, literally.
Any thoughts? I've searched system for a leak and come up dry, literally.
Fleet Mechanic
Joined: Aug 2009
Posts: 1,771
Likes: 9
From: Western Washington
That sounds suspiciously like just not enough fluid in the lines, I say keep going! I've worked on brakes where I had to bleed them for the longest time before I got them clear. And those Dayton calipers aren't just any caliper, those things are huge! It takes an awful lot of fluid to fill them up!
To make things easier I've heard of guys taking a weed sprayer and some hose, filling it with brake fluid, putting the hose over the bleeder fitting and pumping brake fluid in through the bleeder screw until it comes through into the master cylinder. They re-bleed the system normally as well to make sure they got all the air out. I've never tried it, but some guys I've talked with have used it with good results.
Sam
To make things easier I've heard of guys taking a weed sprayer and some hose, filling it with brake fluid, putting the hose over the bleeder fitting and pumping brake fluid in through the bleeder screw until it comes through into the master cylinder. They re-bleed the system normally as well to make sure they got all the air out. I've never tried it, but some guys I've talked with have used it with good results.
Sam
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
I thought as much, but with the master pumping well, the cals should fill up rather quickly. I've never had such trouble getting psi before.
I'm going to go ahead and try the weed sprayer system. Maybe I'll start by opening the bleeder screws on the cals., and opening a line up by the master and filling them up from there. We'll see.
Thanks.
P.S. I noticed A.zone and Harbor frieght had $35 vacuum bleeders that you pump by hand. I thought they would fall apart, or that I'd be there pumping all day. Highest quality cheap Chinese crap.
I'm going to go ahead and try the weed sprayer system. Maybe I'll start by opening the bleeder screws on the cals., and opening a line up by the master and filling them up from there. We'll see.
Thanks.
P.S. I noticed A.zone and Harbor frieght had $35 vacuum bleeders that you pump by hand. I thought they would fall apart, or that I'd be there pumping all day. Highest quality cheap Chinese crap.
Thread Starter
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
I can't get any pressure. I have to be sucking air somewhere. Today I have to pull the calipers again and check them. Something is wrong.
I tried the system with the weed sprayer and filled to master. Still could not get pressure. I bought one of vacuum hand pumps too, and experienced the same thing. It's time to retrace my steps. Ouch.
I tried the system with the weed sprayer and filled to master. Still could not get pressure. I bought one of vacuum hand pumps too, and experienced the same thing. It's time to retrace my steps. Ouch.
Fleet Mechanic
Joined: Aug 2009
Posts: 1,771
Likes: 9
From: Western Washington
It almost sounds like your master is bad, it should create enough pressure to at least make a fluid leak somewhere.
EDIT: Maybe that's where your leak between the master and hydro unit is coming from! Could it be the hydro unit was creating so much pressure trying to push down the stuck calipers it just blew the seals inside the master? The master cylinder shouldn't even have any fluid back that far, unless it blew a seal.
Besides, if you pumped it all up with the weed sprayer any leak in the lines or the calipers would show itself pretty quickly.
Sam
EDIT: Maybe that's where your leak between the master and hydro unit is coming from! Could it be the hydro unit was creating so much pressure trying to push down the stuck calipers it just blew the seals inside the master? The master cylinder shouldn't even have any fluid back that far, unless it blew a seal.
Besides, if you pumped it all up with the weed sprayer any leak in the lines or the calipers would show itself pretty quickly.
Sam
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Lead Driver
Joined: Mar 2008
Posts: 7,174
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From: Near Los Angeles
Sam, I removed and redid the calipers again today. Then I replaced one of the two oem brakes lines on the front. The male half where it screws into the soft line was rounded and I could really tell it it was tight when I used vise grips, so I just r&r'ed it. Then I went over the entire system with a flashlight and checked all the fittings, and found a couple tiny leaks. I also expanded the calipers pistons with air onto the pads/rotors before bleeding. Once I filled it with the sprayer, I only had to crack the bleeder twice b/f it was good.
I have brakes again!! And so far I don't have the phantom brakes applying all by themselves as before! It must of been the front soft lines. It took 6 months for the p/s fluid residue to soften and swell them ... at least I hope that is what the problem was. Now, with the new soft lines and calipers, the problem should be history.
Thanks for the help. Kevin.
I have brakes again!! And so far I don't have the phantom brakes applying all by themselves as before! It must of been the front soft lines. It took 6 months for the p/s fluid residue to soften and swell them ... at least I hope that is what the problem was. Now, with the new soft lines and calipers, the problem should be history.
Thanks for the help. Kevin.