Brakes and a leak on my Ranger

My ‘92 Ranger needs new brakes and has a leak somewhere as well. According to my dad, this was a recurring problem with the brakes when my grandmother drove it (pumped the brakes like crazy). I’ve replaced pads and rotors many times on several vehicles, but not sure where to start finding this leak. Any tips?

Does it require topping off the fluid?
If so, the leak is external and should findable by looking for the fluid. If you’re not already aware, brake fluid is great for removing paint, so be mindful when handling.
The usual suspects on this system, in descending order of likelihood in my opinion: wheel cylinders (bad leaks will show up in wetness on the backer plate, observable from behind the wheel, pulling the wheels and drum may be necessary for smaller leaks, and really minuscule seepage will be spotted by squeezing or peeling back the dust boot on the cylinders), proportioning valve, lines/hoses, all observable by eye, typically. The master cylinder, and calipers are unlikely, but possible. Basically check for seepage/ squeeze/peel back the dust boots (have to get under the dash for the m/c).

If they “leak down” but don’t require fluid addition, check adjustment on rear drums, for good sliding pins on the front calipers, suspect the m/c leaking internally if those check out…

If you do not have any visible leaks, the master cylinder could have issues with the seals. In case of the drums, there should be a residual check valve that keeps the fluid from the drums bleeding back out of the drum pistons. Your drum springs could be over powering that valve allowing the fluid to return back to the main lines.

Alright… clearly I have let this problem linger, and it’s gotten slightly worse. I wasn’t able to find any clearly visible leaks, but I may be staring right at it. I’m hoping to order parts finally and fix this. Anyone willing/free to meet me at the space to help me find the culprit?

If there are no visible leaks the master cylinder may well be leaking into the servo. I had to remove the servo to drain it.

Thanks @procterc, I’ll be sure to look for that! I busted out the chilton manual last night, but haven’t had time to really dive in yet. A few parts are on order that I know will need replacement (pads and rotors), but I’ll have to wait till Sat to begin disassembly and investigation.

Really dumb automotive question… My understanding of this old truck is that the front brakes are the only ones used for braking and the rear are just used for the e-brake… Sound right?

Don’t own a Ranger, but all four brakes will be used to stop the car, the emergency brake will only engage the rear brakes.

Quick internet search says your front brakes are disc and the rear are drums.

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No, the front brakes do most of the braking. The rears do brake as well, they dont take as much load. If the rears are drums, you will have essentially a check valve that keeps the rear drums wheel cylinder full of fluid. If the check valve leaks, the springs on the rear drums will cause the drum wheel cylinders to retract. Thus causing you say to have to pump the brakes when you need to use them. Its basic hydraulics.

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That sounds a lot like what I’m dealing with. Thanks!

Also, not as related, but if you change disc calipers to a larger size. There is a good chance you will have to pump the brakes as well. For instance, My Jeep has larger calipers than what were designed for the vehicle. So what happens in my case, it the master cylinder was not designed to push that much fluid. so what happens is I have to release & push again to get a stiffer pedal. You can’t simply replace the master cylinder with a larger bore size. It would have to be replaced with a longer stroke to give the same stopping power without the pumping. The larger bore master cylinder would make you have to put more force on it to get the same as a smaller diameter master cylinder bore.

This is why on jacks, the pump is smaller than the lifting cylinder.

Rear drum brakes should have a jack screw adjuster at either the top or bottom that is adjusted to take up the excess slop that results from brake lining wear. Most more “modern” drum brakes have some sort of auto adjuster that extends this jack screw automatically. Often it operates as the parking brake is released. So if one never uses the parking brake, the rear drums will progressively get looser and looser with time. And after too much time, the threads may bind up with brake dust to where the auto adjuster can’t work.

Also, depending on year, the ranger could have rear ABS, or a height dependent rear proportioning valve. The reason being that with no load in the bed, you can’t apply much rear brake before lockup. With a bigger load in that small truck, you need the rear brakes doing all they can. I know the ‘94 had rear ABS, and I think it was close to when the had switched from the height adjusting proportioning valve.

@jast @TBJK @kbraby and others, thanks for all the tips and info!

I think I found the leak…

If I’m reading the manual correctly, that’s the rear ABS module leaking like screen door.

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So, I’m reading multiple accounts of people bypassing this valve altogether. Multiple reasons given, but the main one I’m seeing is that the original part lasts a good 20 years but the refurb ones (all that’s available) have a high failure rate.

Questions:

  1. Thoughts on bypassing?
  2. Could this be a faulty sensor as well as a leaky valve?

I think you’re correct in diagnosing the RABS/prop valve as “leaking”.
I’m a fan of RABS on pickups; it helps keep the ass-end in the back, where it’s supposed to be, under braking, especially the “emergency” type.
Eliminating that device is easy-peasy, but don’t do that.
Replace it with a passive proportioning valve would be the way if you want to remove this one for the reasons mentioned. Probably adjustable is the way to go so you can “old school” it into proper range, and let it manage adjusting rear brake bias based on load (how all trucks and many cars survived between 19?? and 1980sish when RABS became “common” thanks to Ford) Also, be aware this WILL turn on the ABS light (unless you include a work-around for eliminating that, which could be as easy as removing the bulb or as hard as tricking the feedback into thinking the RABS electronics are still there and doing their job).

Could there be a faulty sensor as well as a leaky valve?
Sure. I’m not sure why we’re trodding that trail… Is the ABS light on? A quick scroll-through of this thread doesn’t indicate so, but if it is, then a leaky valve might just be the beginning. As wet as that guy looks in the pic, I wouldn’t be surprised if the fluid’s done a number on the electronic in that device (maybe that’s what you mean by “faulty sensor” in which case, "yes’, as opposed to the way I interpret the phrase “faulty sensor”, which I take to mean “faulty ABS/speed sensor”. That’s a hall-effect pickup mounted to the differential housing and working off the ring gear and at this point, I have no basis for thinking it’s awry).

I don’t know if that’s helpful, but that’s a snapshot of what’s floating around in my head as it pertains to this situation.

That’s good advice. Advance Auto has a replacement I’ll pick up and swap out. I’m assuming the leaks are isolated to the valve as it’s leaking from several locations. Basically, I’m hoping I don’t have to run new brake line.

Abs and the parking break light are on, but I didn’t associate them with the sensor as apparently these come on with low fluid. Fill up the reservoir, and both lights go out. I mentioned the sensor because I’m unsure of its function with the valve.

I haven’t messed with hydraulics much, thus my likely newb questions.

I’d expect that to continue, then.

Not THAT big a deal, but us Texas-dwellers are accustomed to not having to meddle with them…

The principle’s pretty straight forward: no air in the line.
Gasses compress where as liquids do not. Need liquid in the line to operate hydraulics (otherwise, they’d be called “pneumatics”). Brakes are no exception: purge the air, keep “solid” fill of fluid between the primary and secondary (master & slave in pre-2000’s lingo) cylinders to do their respective jobs. But yeah, things like RABS and prop valves can certainly spice up the mix… Nothing really magical about them, either, tho, so you got this. :+1:

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Cuss words

image

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Bleeder valve? Or the end of a brake line? I can’t tell. Sucks either way.

Bleeder valve. Gonna try to get it out, but I’ll probably have to replace the wheel cylinder

So very thankful it is on the wheel cylinder and not on the ABS valve block.