83

Been having a hard time even trying to title this thread so I've been putting off asking about it.

For the last couple weeks, I somewhat regularly feel resistance to rolling forward when first moving the truck. I park at home or at work, use the parking brake (always), then get in, start the truck, release the brake, and it feels stuck. Even if I'm on a slight decline, it won't roll forward, even when I let out the clutch. Normally the truck would start to move forward just at idle, letting out the clutch and hardly touching the gas, if I give it any gas at all. But not when this happens. If I go just as easily in reverse, just letting out the clutch with little or no gas, it will move just fine. Put it in 1st to go forward, and it feels like there's a rock or big stick right in front of the tire that stops me. Will roll fine in reverse, won't roll forward.

When I had a shop replace my rear wheel bearing and seal, he had to replace one whole backing plate, and he cranked my parking brake much tighter than it had even been. It works better than it ever has, but I think it could be loosened a bit.

Anyway, my first thought is the parking brake sticking, but would it make sense to stick trying to move forward, but not stick moving in reverse? It makes me worry that it's an axle or gear issue. Sometimes it feels a little like drag, like there's just something holding it back a little, but other times it really feels like hitting a rock. It starts moving a few inches and stops suddenly. I can absolutely push through with more gas pedal, but it won't roll forward smoothly without throttle. No noises or grinding, nothing rough, just a gentle "stop" when rolling forward.

Any thoughts or things to check? I keep meaning to pull the rear drums and look around and spray everything down with brake cleaner, but I haven't managed yet.

2ToyGuy

Have you tried jacking the truck, thoroughly blocking the front tires, naturally, and tried spinning the rear tires manually? Of course not in gear, and parking brake off? Is there any resistance, on either tire? Either direction?

When the parking brake is off, is the cable actually going to the wheels tight at all? If you can play it like a 1 string guitar, it's adjusted way too tight.
Are the bell cranks rusty? Have you tried a small shot of WD-40, 3-in-1 oil, whatever to make certain they move freely? Have you tried adjusting the bell cranks according to the FSM? Have you tried adjusting the cable a bit?

Have you tried adjusting the brake shoes with the star wheel to loosen them a little? Sometimes the drums aren't perfectly round and will rub the brake pads a little. IIRC, even if you get them a little too loose, backing up and hitting the brakes adjusts them. May take a few shots to get them perfect, but...

Have you tried bleeding the brakes, all the way around, including the LSPV? When things are sticky, have you tried opening the bleeder valve to see if some pressure is caught in the system someplace? Sometimes the soft brake lines can have the inner liner collapse, trapping fluid under pressure downstream of them.

Have you checked that the brake pedal is properly adjusted? So that the master cylinder is returning all the way, releasing ALL the pressure?

Are you absolutely certain the transfer case isn't in any part of 4WD? IOW: there is no 4WD engagement of any sort. 4H, 4L, nothing?

Anywho, good fortune, and let us know what you find
Pat☺

83

Thanks. At some point I'll dig into the rear brakes, I just wanted to see if anyone had other ideas in the meantime. I'm being a little lazy, I'll admit, but in the summer I live in my camper, which means a couple hurdles. I'm often off-level, always in the dirt, and can't have my truck down for long because I need to get around, and need to move the trailer. So I dig into things when I house/pet sit for friends, if they have a garage or driveway. The last couple times I've been at someone's house, I've spent my time working on the catalytic converter.

I went through adjusting the drums a couple winters ago so it's kind of fresh in my memory. I'm staying at a friend's house in a couple weeks with a garage, so I'll open them up then. They have a floor jack, too, which is key.

I did a lot of work when I first bought the truck, but time flies...I flushed the fluid, but that was now 5 years and 100,000 miles ago.

Shouldn't be any 4wd engagement. My truck has the mechanical shift lever for 4wd, and indicator light. Shifter is in 2hi, no 4wd indicator light.

2ToyGuy

I understand. You do what you gotta do, after all.

Let me just add a quick note, if I may: Over time, the brake fluid absorbs moisture from the air. This degrades the fluid. If it's any color other than a straw tinted clear, it needs replacement. After 5 years, I imagine it needs to be changed. Badly. I know, you'll have to wait until you get it to where you can do it, but if it were me, I'd do it as soon as you could.
That's a good chance to see if you have pressure trapped in a brake cylinder, or the master, since you need to open the bleeder valve of each brake cylinder to bleed the bad fluid out.

Don't forget the LPSV! A lot of people do. Not ME, of course. <AHEM> Nothing to see here. Move on, move on. This isn't the idiot you're looking for...

Good luck!
Pat☺

83

Regardless of whether it's time in the maintenance schedule to flush brake fluid, could that cause sticking when rolling forward, but no sticking when rolling backwards?

2ToyGuy

It depends on how the rear brakes are adjusted. I can see it if the pads aren't properly adjusted. Especially could see it if the master cylinder isn't adjusted just right, and holding a little pressure in the rear, or front, brakes.

IMHO, and please bear in mind I am NOT a brake professional in any way, it's the parking brake adjustment, or the rear brake pad adjustment.

Also, have you checked that the front calipers are retracting properly, and their mounting bolts aren't even the slightest bit loose? If they're just the littlest bit loose, they might be binding a little one way, but fully free the other. The front calipers can cause all kinds of troubles.

The LSPV can as well, affecting the front brake. Like if there's dirt caught in it, and not allowing the fluid to flow correctly,

Like I said, though, I am NOT a brakes guy. I am a radar tech by training. The loose bolts on the front caliper problem happened to me, that's how I know. Yes, it was my fault for not torquing them down correctly, but...

Good luck to you!
Pat☺

83

Alright. I'll check, hopefully next week. It's probably about time, at 23 years and just under 300,000 miles, to really go through the brake system anyway.

Thanks.

fierohink

Sticking going forward but not backward sounds like the rear brakes weren’t assembled correctly. A clip or spring isn’t right or the shoes are in backwards.

83

Thanks, I'll check that out, too. Would that be obvious to brake novice using a photo or diagram of correctly assembled drums?

Thing is, it doesn't happen all the time. Off & on. It was starting to happen quite a bit for a while, then hasn't really been happening lately. Not sure if that still tracks with your guess?

2ToyGuy

TBH, I; personally, for what it's worth, can't see a difference between the two shoes a drum brake uses. Looking around the net using duckduckgo, etc.
Having said that, since fierohink said that it's possible that the whole thing may have been assembled backwards, obviously there IS a difference. Just because I can't see it means nothing. I did the shoes on my 87 4Runner, but that was 20 some years ago. I don't recall the details about the shoes themselves. Mainly what I remember was what a PAIN stretching the springs into place was. Even with the specialized drum brake tool. I spent more time doing the springs than all the rest put together. Bleh.
Even in the FSM drawings, I can't see any way to assemble the shoes backwards. Once again, though, this all means absolutely nothing. Once you get the new shoes, the differentiation may well be blatantly obvious. Markings on the shoes, an included instruction sheet, something.

Good luck to ya!
Pat☺

83

Didn't have time to bleed/flush/replace brake fluid, but I did jack the truck, spin wheels and take out the front pads to look at things. Calipers aren't seized, but I think I knew that. Rear wheels spin freely. Front wheels have some drag, but still easily spin by hand.

83

Pulling apart the front brakes seems to have fixed things, at least temporarily. I took off the wheels, took off the brakes, pulled the brake pads. Looked everything over, compressed the calipers to make sure they moved. Sprayed it all down with brake cleaner. Didn't even take the rear wheels off because they spun freely, without even any noise of slight drag.

So far the hesitation hasn't happened again. Not sure what that means. I'll still get around to flushing the fluid before long.

At just shy of 300,000 miles, this truck is starting to have constant, though mostly minor problems. That's ok. Things eventually wear out. It's still reliable, still the only truck I want, and still cheaper than a truck payment + full coverage insurance.

2ToyGuy

Could possibly be one of the flexible brake lines inner liners may be collapsing, holding some pressure on the calipers after the brake pedal is released. It can be fairly random as to when, and how much pressure it can hold. Anywhere from a little pressure to the full amount applied to the brakes. It's easy to determine which line it is, if that's the problem. Just wait until it happens again, and open the bleeder valves, one at a time. If the problem suddenly disappears with a small squirt of brake fluid from the bleeder valve, you found the bad flexible brake line.

Finally, and I don't mean to carp about this, but it's important. When you bleed the fluid out for clean fluid, when you come to the LSPV, last in the bleed order, take the bar that runs down to the axle off at the axle end, and move it through the valve's entire throw. Either before, or while, bleeding it. It will help loosen up much of the crud that builds up inside the valve assembly, allowing it to be flushed out. Either that, or if you feel brave, take the LSPV off and strip it down, to clean it out. Then put it back on and bleed it out normally.

I wish you all the best!
Pat☺

83

Update.

What I did was to tough it out until my truck went into the shop.

I noticed at the beginning of November that my drivers side rear axle seal was leaking again. I assumed that was probably the locking issue...

History:
My right rear axle bearing went out last spring, the truck had to be towed home, and so I had a local mechanic replace both bearings and seals (both sides). Right side started leaking a month later. He "fixed" it again. Same side started leaking again two weeks later. So I gave up on him and took it to the mechanical I really like, but who is 2 hours away. He said it was a hack-job...$600 later with all new parts including the retainer and brake backing plate (both mangled beyond recognition), I was back in business.

Anyway the left side held up just over a year, but finally started leaking too, so I knew more or less the issue (previous mechanic hack-job), and set an appointment with my trusted mechanic. I figured it was the currently leaking side causing the lock-up, but...

After having my brake-locking issue happen a couple times on gravel, it was obvious that the right rear wheel was locking up. The one my trusted mechanic worked on. So I had him check that while he was replacing the left seal. He said he sanded down the pad and cleaned things, and bled the system (didn't flush it, so that's still on my to-do list). It definitely isn't happening anymore. Because of my multiple axle bearing and seal issues causing major leaks, my rear drums are pretty oil-soaked. But even though the truck has 300,000 miles, and I tow with it, there's still plenty of pad left! So he didn't want to replace them, but said if it happens again, then I probably should replace them. We'll see.

So I don't 100% understand the issue except that it was caused by oil soaked pads, which my mechanic is hesitant to replace since there's so much of them left, and fixed (whether temporarily or permanently) by sanding. We'll see.

5 Fists

From everything I've ever read or been told there is no way to save oil soaked pads and that they should always be replaced. No matter how much life is left on them.. but I'm not a mechanic, so I very well could be wrong. It's the first time I've heard of trying to save them and re-use, but I'm sure it happens all the time. Seems strange to me though. I would think the oil would soak and seep into all the pad material, not just the surface which you could sand off. Just my thoughts.

83

I had always heard the same thing. Both the mechanic who originally did my bearing/seal work (who I do actually trust, just not to do jobs he doesn't have the tools for), and my favorite mechanic both said "don't worry about it, they'll probably be ok". So, I don't know. They certainly work fine. Until one of them started grabbing anyway

The one I like better who has done the recent work is a skilled, knowledgeable, OCD-type guy. He's the owner of the shop and the only mechanic (I assume no one else is up to his standards), the floor of the shop is always spotless, and he always does good work. So if he tells me they'll probably be ok, I won't argue.

Malcolm99

You can’t use the oil soaked pads because they swell and will continue to swell causing the brake drag.

If you don’t measure the ABS ring like pictured below from the ABS ring to the bearing and put it back in its original location it’s likely to leak, 0.5mm off is exceptable as the bearing has 0.25mm defection and the press is only so precise and you don’t what it going on to far, if it is put on to far by 2mm the seal will ride on the edge of the retainer and leak, you can mark the retainer with a sharpie to see where the seal is riding and maybe move the seal a bit, but best to locate the rings correctly as it was from factory, you should use this tool so you can reuse the expensive OEM abs ring and retainers, that cost alone pays for the tool practically, if you read the FSM it says to hack the rings off and usually people hack into the shaft, if the shaft is badly cut the oil will leak past the retainer and shaft, you can add silicon to fix it when installing the retainer or buy a new axle shaft. I’ve done a few of these now and the taco was a similar measurement even with the different bearing styles you see on the later 4R and Taco, but best practice is to measure it exactly like below and return it to the same location, the OEM bearings, retainer and seals are a better fit and seal than aftermarket. Usually the clogged diff vent causes an axle seal leak, so wise to relocate it or give the OEM breather a spin to free it up every oil change.

83

That's the tool my local mechanic doesn't have, and why it turned into a hack job. He said if he worked on more Toyotas he'd get one, but this is a ranch town and most people are driving domestic trucks.

I occasionally check my breathers. They're clear. I don't see much mud around here. Neither of my seals leaked until I had the local mechanic replace the bearings and seals.

akwheeler

I don't know about the Swelling mentioned by Malcolm, but here's what I can tell you.
First, I've done hundreds of brake jobs.
Second, when the brake shoes get soaked with gear lube you can't clean it all off/out of the lining.
Third, rather than lubing the braking surface and making it slip it will make the brake very "grabby".
once the oil gets into the lining no matter how much you clean them more will leach out when the shoe gets hot.
Most rear drum brakes have a shorter lining on the front brake shoe than the rear and if you don't notice you can end up with both front shoes on one side of the truck or the front shoe mounted in the rear position.
If you have the longer lining to the front side of the drum it will also make the brakes "grabby".
Another issue that catches people sometimes is brake adjustment, if you (or anyone else) adjusts the parking brake without first adjusting the drum brakes it can lead to improper activation of the starwheel adjuster and could end up dragging brakes and warping drums.
For drum brakes to work properly they must be clean and dry with a smooth surface on the brake drums that is not past the maximum inside diameter stamped on the drum.
Some Toyota drum brakes have a bell crank assembly on the backing plate, these also cause a lot of issues when they seize up.
For proper adjustment loosen the parking brake cable, make sure all bell cranks and cables move freely, adjust the star wheel until the brake drags, then back it off until it spins freely. THEN adjust the parking brake.
Sorry, this is more like a rant than anything else.

83

Well it sounds like I can expect this issue to come back. When it does, I'll replace the rear pads, and likely do a complete overhaul of the drums, since it's all original back there. Right now they aren't the slightest bit grabby.