rear brake problems

[steve89ranger]

i have a 89 ranger extended cab. just bought the truck so not sure if it is having trouble stopping on snow and ice because it is so light. if i start the truck up no warning lights are on, then i drive it for about 5 miles then the brake light and the rear antilock light come on. it stops fine on dry pavement, but we got our first snow and i tried to stop yesterday, that didnt work. the front tires lock up and seems like the rears arent working at all. where do i go with this?

 

[flagport]

Steve,

I'm not fully versed yet on the electrical interfaces involving your description of the brake light and rear ABS light coming on after approximately 5 minutes of driving, but I can address why your rear brakes may, in fact, be non-functional, and offer a simple troubleshooting solution to find out.

I recently overhauled the rear drum brakes on my 92 2.3L Ranger, and installed a new wheel cylinder on the right side. During the attempt to bleed the brakes, I discovered that neither rear bleeder valve would pass any fluid. After some study in the the brakes section of the forum, I determined that this was likely caused by a clogged "due to age, and probably never been flushed" ABS Hydraulic Valve. This valve is attached to the inside of the frame just below the driver's left heel, and is fairly easy to access and R&R. Troubleshooting involves taking one hose off (the rear first, and see if you get fluid out of the valve, if not take the front hose off and see if you get fluid. If no to the first, and yes to the second, it's likely clogged. Your main problem is going to be getting the input and output brake lines loose from the valve without rounding off the nut heads, at least that was my problem.

Clogging of this valve due to rust or corrosion over time appears to be fairly well-documented occurrence. So, there's like a number of older Rangers running around out there with inop rear brakes.

Replacement cost is around $120.00 for the unit, cheapest I found was at Auto Zone. There are some forum threads which support bypassing this valve, due to its cost, and living without ABS.

Hopes this gives you a place to start.

Happy Holidays,
Ron

 

[cocoasranger]

+1 on this. Have an 89 Ranger, fronts locked in snow, no fluid out of rear bleeders, ...blah, blah, blah. Had a new rabs unit installed and bled for $175; now brakes are fine. Flagport is right on with every point.

 

[MAKG]

It's indeed rather common (and I suspect it's a source of quite a lot of brake upgrade questions), but most of the time there are NO lights.

I'm following up an RABS light problem at the moment that MAY be something like yours. Either there is a problem with the rear brakes (e.g., a leak), or the RABS electrical connector is disconnected, or there is a wiring problem between the RABS valve and the module, or the valve is fried. I believe those are the only possibilities that light BOTH lights.

In my case, the valve definitely has an open circuit. Yours is probably different, as the symptoms on mine are that the rears work as normal power brakes, just no ABS. In order to make the rears DEAD, you would need something else in addition or instead. A leak in the rear can explain it all, but you could have a plugged valve AND an open circuit, for instance.

Plugged valves can definitely be tested for as described above.

You can get the diagnostic code from the RABS by grounding the test connector (it's near the parking brake pedal). The open circuit code is DTC 4.

 

[PANTERA]

No intention of hijacking this thread, but I have a 92 with the same problem. Drive for about 5 min when the brake light and RABS light both come on. However, when coming to a stop, it seems like it takes a little bit of effort, but when it slows down to about 5 mph the rears lock up. Any help would be greatly appreciated.

 

[rurouni20xx]

re to pantera

sounds to me pantera that you have a clog in your line on the rear making your brakes not return the fluid and boil locking up the brakes, ive seen this on four wheelers that have bad master cylinders or old brake fluid, the master cylinder will have a spot where the valve doesnt completely return so when heat is generated in the brakes causing them to swell the the heat makes the brake fluid boil and has to relieve the pressure in the master cylinder, however if the fluid has nowhere to go i.e. a clogged line, sticking/frozen wheel cylinder or sticking master cylinder valve the brakes actuate and lock up. this can also be caused by a sticking valve int he rabs module which would explain why you asked about another yr rabs module fitting in another post, this would make sense but to rule out any other factors such as crap brake fluid w/ impurities and junk try changing and bleeding your entire brake system w/ fresh fluid and pump the lines thru, then check your wheel cylinders and calipers for frozen/sticky valves and make sure your master cylinder w/ the engine not running feels smooth and completely returns b4 trying to replace the rabs valve, it may take alot of time but in the end it may just save you the 130 bux on the valve and just cost you 20 bux on fluid.

 

[torthen]

How about only one brake (rear right) not running any fluid when trying to bleed it? I bled the left rear brake with no problems (gunky ugly fluid came out and a couple bubbles), but the rear right brake wouldn´t bleed any fluid. I pumped the pedal various times, I even drove a while with hard braking, and then tried to bleed it again but no fluid... If it were a bad valve, wouldn´t fluid stop from BOTH rear brakes??

Thanx!