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brake problem: please help, im stuck in price utah towing a load

Gravy

Gravy

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brake problem: please help im stuck in Price UT towing a load.

94 suburban 2500 6.5 TD.

Lately towing I've had a problem on the rare occasion that I lock the brakes up towing that the abs goes insane and locks the brakes solid even when i let off the pedal.
I'm towing my jeep from slc to moab.
It did it earlier today on my way and I was able to switch the key off and then on and have it release. When I stopped later for fuel, I checked the fluids and added maybe an ounce of brake fluid, but it was at an acceptable level. The little rubber seal for the master cylinder cap came off and it was super hot and kinda sticky. I couldn't fit it back on because it seemed to be swollen up larger than it should have been. When I tried to force it in, I tore the rubber so I discarded it and put the normal cap on without it. And headed out. I assume the cap is just a normal breather cap?

So fast forward (60 miles). I get into Price, UT and I have to put the pedal to the floor to stop.
Visually the system has no leaks and the brake fluid is not low, but it seems dirty, (no less than before).
I'm towing a 4500 pound jeep on a dual axle trailer so I'm stuck until I figure this out.

Posting from my phone.

Now I'm at aq gas station and here is what I've done so far.

I added some power steering fluid because it was slightlys slighty low.

Attempted to blead the passenger front brake while off to see if there was air in the line. Pumping the pedal did not seem to build pressure like a normal vacuum assist system.

Attempted to bleed with the motor on and again no increase in pressure when pumped and only pressure at the lowest part of travel. When I release the pedal I rises slowly and has no pressure if I attempt to pump again quickly.

No bubbles in the line viisually and no spitting like a line than has air in it.

I tried bleeding the bleeder on the abs module that is furthest forward while the motor was on and no fluid came out at all. Weird?

What's broken?
What do I do?

My wife did a search that came up with the proper way to bleed the system as:
Master rear then front
Abs module rear then front
At the wheels.

It didn't say to do bleed it on or off.

Please help.

Stratton.
 
No but I unplugged the abs module (red and black wires to the module)

ZERO BRAKES. Tried bleeding the abs module again just one. My guess is the master Or abs module took a dump.
 
I unplugged it with no change in function. even with the car off I should have pedal pressure. I bet the master is gone
 
It has hydro boost.

No ebrake stuck, dot3 or dot4 fluid always.

Here's my hypothetical ramblings in a parking lot at 11pm:

Master/ hydroboost starts going bad occasionally locks the tires. This time locks the tire. Boils the fluid and as a result kills the rubber master cap gasket thingy. I really no very little about hydroboost accept the concept of how it works.
 
Gravy said:
It has hydro boost.

No ebrake stuck, dot3 or dot4 fluid always.

Here's my hypothetical ramblings in a parking lot at 11pm:

Master/ hydroboost starts going bad occasionally locks the tires. This time locks the tire. Boils the fluid and as a result kills the rubber master cap gasket thingy. I really no very little about hydroboost accept the concept of how it works.
Click to expand...

Locking brakes would be an ABS problem
 
Is your brake light flashing any codes?

I dont think ABS can apply the brakes, so for locking with no pedal must be a master cylinder issue. Have you ever lost fluid all the way and had to refill the brake fluid reservoir? If having it worked on replacing these master cylinders has to be done by the book by a competent technician, its not as easy as swapping.

How are you bleeding them, its a two person procedure if using the pedal and MUST keep constant increasing pressure on the pedal while momentarily loosening the valve at the wheels.
 
Master cylinder is done. With unequal pressure the abs could do weird things. I've bled without engine on with a mighty vac[sucks the brake fluid through] with no problems. Bench bleeding the new master will help reduce the air in the system.
 
Two person bleeding with my wife. I've never been lower than the "min" line on the reservoir.
I haven't checked the codes. Didn't know the brake light showed a code unless the check engine light was on. Brake light is only on when I pedal it to the floor anyways. Plus I don't have a code reader here at the edge of humanity. :D

When this little town wakes up ill see what a mech has to say
 
It can also store code i believe. There are two certain pins you jump on the obd-1 connector and you read the brake like just like a service engine soon light. It blinks a number of times, which results in a code. i think i found the codes on fullsizechevy.com or something like that.
 
I ebraked it 6 miles into Murdock chevy who actually has a hydroboost master in stock. We'll see what they have to say. :D
 
A swollen master cyl rubber cap comes from only one thing pwr str fluid in the brake fluid,it will take out the master cyl first and then the calipers next.
 
Your emergency brake light or the "brake" light will flash codes if there are ABS problems. The SES light will come on if there are drivetrain problems. Jumpering A and B on the OBD1 port and turning ign to ON will cause SES light to flash any stored codes. I am not sure if that method causes ABD codes to come out.
 
6.2 turbo said:
A swollen master cyl rubber cap comes from only one thing pwr str fluid in the brake fluid,it will take out the master cyl first and then the calipers next.
Click to expand...

I agree. The swell up and ruin brake parts with the wrong fluid is a warning in most owners' manuals. Had an oil change done a Jiffy Lube or the like lately? It is more common than you think to get a free top off of the wrong fluid.

Curious as to how this would happen with a mechanical failure. Supposed to be a drain port between the master cyl and the hydro boost unit. So if the hydro boost starts leaking it drains out and not forced into the master cylinder.

The rubber cap that was understandably 'tossed' is critical to keeping brake fluid in the reservoir and water out of the fluid. Hot and swollen does indicate a reaction going on.
 
WarWagon said:
I agree. The swell up and ruin brake parts with the wrong fluid is a warning in most owners' manuals. Had an oil change done a Jiffy Lube or the like lately? It is more common than you think to get a free top off of the wrong fluid.

Curious as to how this would happen with a mechanical failure. Supposed to be a drain port between the master cyl and the hydro boost unit. So if the hydro boost starts leaking it drains out and not forced into the master cylinder.

The rubber cap that was understandably 'tossed' is critical to keeping brake fluid in the reservoir and water out of the fluid. Hot and swollen does indicate a reaction going on.
Click to expand...


Isn't it also to keep the system closed....(ie. Air)
 
The fluid keeps that air from going into the lines, unless you let the reservoir empty then you are asking for serious trouble. Cap is probably to keep that corrosive stuff locked up tight with not fumes when it gets hot.
 
WarWagon said:
Curious as to how this would happen with a mechanical failure. Supposed to be a drain port between the master cyl and the hydro boost unit. So if the hydro boost starts leaking it drains out and not forced into the master cylinder.
Click to expand...

There IS a drain hole. You can feel it on the front bottom of the hydro where the master bolts up. I just went through a hydro swap because the hydro was leaking power steering fluid from the front seal and coming out that drain hole.

Don
 
I took it in to the Chevy dealer in Price on Friday morning.

Ended up that I knew quite a few of the techs at the dealerships (hardcore wheelers are a tight crowd here in Utah).

Went through everything with them and found a bad valve in the ABS module (hence the sticking pedal) and the Hydroboost master was toast.

The swollen rubber master cap gasket was caused by the heat from boiling the brake fluid when I drove it to the side of the road with the brakes locked. Not because of the wrong fluid. Chances are that since the gasket is there to prevent fluid spills and to keep moisture out and that I only drove 60 miles without it; that it probably had little effect on the brake failure. The brake system was on it's way out.

Also one of the bolts had backed out of the harmonic dampener and the spokes of the crank pulley was smacking into it, which caused the rubber between the pulley and dampener to crack, then the belt would slip when the pulley would stick. Apparently it's been running like this for a while: just another testament to the beef of the 6.5 motor :)
(But this explains my Charging issues and most certainly could have caused less powerful brakes due to the serpentine system spinning then stopping and then spinning again).

To make a long story short between a new ABS module, new hydroboost master and new harmonic dampener the repair quote was $1600, AND they would have had to order the 4 wheel drive 6.5TD specific ABS module from Michigan, and it wouldn't get there till Tuesday.

The techs at the dealer kindly offered to tow my junk out to a hotel and tow it back and forth to the trails in Price so we could wheel with them over the weekend (Price has some world class trails). But... Stuck in Price 5 days is not my idea of fun especially since my wife and I both have to work Monday.

I only paid $1300 for the Suburban in the first place so you do the math...
They offered me a VERY generous trade considering my situation... and the fact that one of the service writers at the dealer needed a donor 6.5 for his truck. The motor was still running strong so we both got the good end on that deal.

So we cleaned out the Burb and we ended up with a used v8 gasser Super Duty for a ridiculous deal. I'm immensely grateful for how helpful they were. So we loaded up and shot out to Moab Friday evening to finish our trip.

Farewell 6.5 Burb, you did me right until the end, and you'll be missed :hello: Hopefully your motor lives on in another truck :agreed:
 
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