Hello everyone, I'm new here I have a 1990 4x4 ford Ranger, the little truck was purchased in early 2008 as a work truck but has ended up becoming my main vehicle, it has been a good truck for the most part but know I am having some brake issues, well have been having for some time but they seem to come and go. Usually it happens when I have to hit the brakes hard, the rear brakes lock up, I replaced the master cylinder months ago and thought that fixed it, then a month later it happened again. The last time it happened was friday, the time before that was in march 09'. I have searched this online and found numerous try this but the original poster never comes back to say if the problem is fixed or what fixed it. My ABS light DOES NOT come on when this happens, it does function properly, it illuminates when the key is turned on then goes off. My parking brake no longer works either but I think that is from me "driving thru" the locked up rear brakes. I plan on replacign both drums and shoes within the next week but would like an option to repair the locking up issue. Thanks.
No I have checked them, the rear brakes function properly, other than no parking brake, up until they lock up. I could see something being jammed if they locked up all the time but not every few months. I have read online that possibly the abs valve, the brake line, or wheel cylinders but know one ever responds back with what did fix the problem. I guess I can start with the line, cylinders, drums and shoes and go from there.
well I changed the shoes and drums, the left side was completely worn dowm, the right side not bad at all but changed the drum anyway. I ran it on stands after replacing them and the left one locked up so I cracked the line at the wheel cylinder to get the drum back off. I checked the adjuster and it was ok, so I cracked the line and pressed in the shoes to, then put it back together and test drove it. It seemed fine so I am thinking either my wheel cylinder was over extended if thats even possible. If it locks up again I am going to release the pressure by breaking the line loose and then replace the wheel cylinder. But if it was the cylinder then cracking the line shouldnt affect it, maybe bad springs on that side?
One other thing i just noticed looking at chiltons online, one pad is completely backed with brake pad, the other shoe has about 3/4 backed with brake pad on the new ones, now i put them on just as i took the old ones off but which pad is supposed to go where because the manual i found online shows the full shoe going to the rear.
Good man. The shoe with the short lining goes to the front (leading shoe).
And it is possible for the wheel cylinder to over extend and be difficult to press the piston back in. However if it will only press in with the bleed screw open it usually means something is restricting the fluid flow back to the master cylinder.
If you have ABS, then that is likely your problem, even though you do not get a warning light on the dashboard. The only reason for the pistons to stay extended is corrosion in the wheel cylinder or pressure in the brake line. You released the pressure by opening the bleeder, and the brakes released, just as they should. The only reason for pressure would be if the ABS was keeping the line pressure up after brake application.
I am assuming the "driving through" a locked brake means pushing harder on the gas pedal until the brakes release or they get hot enough to lose their effectiveness, which either way will wear the shoes quicker. Apparently one side is sticking more than the other. You could also try new retracting springs, as the old ones could have lost their strength from being over heated(possible, but not likely).
I would suggest that you test the ABS system. If it is the original brake fluid, it would likely need to be flushed. You'd be surprised how bad brake fluid can look, even though it is supposed to be a sealed system.
I understand the problem with the RABS, I have read alot of posts with this similar problem but when i had it up on stands the only side locking up was the left side which leads me to believe the RABS valve isnt the issue, not saying it cant be but would expect it to be locking up both sides. The right side wasnt worn nearly as much, as a matter of fact it looked almost new. The shoes are on backwards, which means who ever owned the truck before me put them on backwards, I am going to leave it like that until I get a new spring kit later today. I will post back and let you all know how it is goes.
Check to make sure that the adjusters are on the correct side. Given that the shoes are installed incorrectly, they could have done just about anything...
The primary shoe has a different compound, or they did, but anyway, the forward shoe gets pushed out into the drum, and acts as a 'jam' to push the rear shoe even harder into the drum. I believe they are called 'self actutating', but the deal is that you don't have to push as hard as if they were fixed at the bottom. If the springs are installed wrong, the RABS will let the brake fluid out of the wheel cylinder, but it may not get pushed out as much as was designed, and then the RABS closes the valve, thinking it should have let out enough fluid to release the brakes... and it locks up.
Get a book, with pictures. When you get old like me, you will believe in digital cameras as a Godsend. You can look at the LCD and see what you futzed up, or left out, or put into the wrong slot or whatever. Even print out a good sized paper print.
Thanks for the reply, well i redid the shoes properly this morning and rechecked the adjusters they are marked so I did verify they are on the correct sides. I did take pics before I took it apart just in case I had issues. I am a diesel/construction equip. mechanic by trade but they are quite a bit different than auto's. Anyway as I was saying I redid the shoes to put them on properly and then again ran it on the stands to test them, after applying them hard both sides did lock up. I have the rear flex brake line but from observing the line I cant see it collapsed so I am going to believe I need wheel cylinders and a new RABS valve. I may go ahead and recheck everything again against chiltons online and make sure everything is correct. Now the left side is constantly rubbing so maybe a wheel cylinder on that side?
One other question will my results be different running it on stands than running it on the road since it has no weight on the tires in the air?
EDIT: another thought the hold down springs on the left side are weak I am going to replace them but could that be the issue on that side?
sorry guys I know it seems like I am throwing alot out there but it is better to learn from the experience of others than to throw a few hundred dollars into parts that might be the problem. Would rather try the cheaper things first.
I had this problem last week(99 XLT, 2wd, 131,000) when I drove in a funeral procession-on the way to the cemetary, because we kept stopping quickly and numerously, as we "caterpillared" on the way, my rear brakes locked up. I think it has something to do with the RABS, as I only have rear ABS-they put a "valve" on the rear brake line coming out of the master cyl., that I understand(not for sure) holds a certain amount of brake fluid under pressure to the rear brakes. I was a little concerned i wouldn't be able to get home without backing off the brakes-we spent a good hour at the grave site, and when I got in to go home, the brakes were fine. No problems all week going to work or anywhere for that matter....
I was trying to avoid buying that valve but looks like I will have to, unless someone here has any other ideas. I am going to get a spring kit and replace that as well. 7 bucks for the kit and I know I need atleast a new hold down spring on one side.
ok just an update I changed the wheel cylinders and replaced all the springs, the left side still has some drag but not as much so I am going to run it and see how it goes. I will update in a week or two to let you all know if I have to replace the RABS valve.
brake fluid is hydroscopic which means it absorbs water usually through the rubber brake lines and the seals on the wheel cylinders i flush my brakes at least once a year and haven't had any problems. brake fluid is cheap,vehicles are not.
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