I have a question about my brakes system, just bought this truck a few weeks ago and the brakes work but don't lock until I add a LOT of pressure, and it takes a couple seconds sometimes. This is working fine so far but in my city there is a lot of stop and go traffic sometimes, and wouldn't like to not be able to stop sometime and rear end someone.

Anyways I am planning on checking my whole brake system and re-doing whatever is necessary. Not sure if I'll need new pads/shoes, or if it just needs to be bled, or if possibly it needs a new brake booster or master cylinder *crossing fingers it doesn't*. I don't know a whole lot about brakes or trucks in general, but replaced wheel cylinders and brake shoes on my old Isuzu Pup I had, so I am needing some direction here.

First, I plan on bleeding the brakes to see if that makes any difference. What order do I want to do them in? Looks like it's an 8mm, at least for the back brakes, but I don't have a brake wrench that size. Tried using a box end but it started slipping. On the front brakes I could only find the bleed screw, where the fluid comes out, and not where I want to attach the wrench, am I missing something or is it the same screw?

I plan on just leaving the truck on the ground, since it's pretty high up and I'm not that large of a guy, and bleeding one brake at a time, having my girlfriend hold the pedal for me. I've read that you also need to bleed the master cylinder (I believe), at some point in the sequence. Does this apply to my truck?

So pretty much, at this point I am starting with bleeding the brakes, and I need to know:

1. What order do I do the brakes in?

2. Will I need to bleed the master cylinder as well?

3. Where is the screw I need to turn on the front tires, and on the back it's the one with the brake line going into it correct?

4. Will I need to pick up some brake wrenches, since standard ones seem to slip? I was looking at the kind that is the round end of a box end wrench, but with a small gap that the brake line can get around.

5. Does my plan sound ok, as far as doing the standard 2 person brake bleeding procedure? As far as I remember, my girlfriend will need to pump the brakes a few times and then hold it down all the way, then I open it until no more air and just brake fluid, and then close and she lets up on the pedal and we go to the next. This sound right?

I know it's a lot of questions but please bare with me I'm learning, only my second time working on brakes. Thanks guys.

Zac

 

I think it could be the vacuum pump. When I bought mine, you had to stand on the brake pedal to get them to engage. A new vacuum pump fixed it for me.

 

I can't say that it's THAT bad, I can usually stop within a half meter or a meter, haven't measured it yet. I don't have to put an insane amount of pressure on it, just more than I've ever experienced before. Feels kind of like my Isuzu did when it had a broken wheel cylinder and wouldn't keep pressure.

Not trying to question your advice I'm really just hoping it's something easy (and cheap)! Is there any way I could test the vacuum pump, and if that's bad is it an easy or cheap fix?

Zac

 

Does the pedal feel more squishy, or solid?

It does sound like it could be the vacuum pump (small belt driven pump on the lower passenger side of the engine). You'll see a large vacuum hose going to the brake booster, pull the hose from it and see if it's pulling any vacuum with the truck running, you'll be able to feel it with your hand if it is. If it seems to be okay, then go through the brake bleeding procedure.

You want to bleed the brakes from the wheel furthest from the MC to the closest (passenger rear, driver rear, passenger front, driver front). All the bleeders will have a hex fitting to remove them with a wrench or socket. If one doesn't, it is stripped and you'll need to buy a replacement (even better to just replace them all) and get it out of there with some vice grips. Spray all the bleeders down with penetrating oil (I use PB Blaster) and let them soak before trying to remove them, you don't want to break one off in the cylinder/caliper. Make sure they all loosen and let fluid out before actually bleeding the system, makes the job quick and keeps the girlfriend happy. Make sure to top off your MC before bleeding. Have her pump the brakes 3 or so times a hold them down, and let some fluid (and air) out, then close it up. Repeat (while making sure to top off the MC as you go) until clean fluid comes out of all the bleeders, then top off the MC one more time.

If it does come down to the MC or booster needing replacement, they aren't that expensive, and can be knocked out in an hour (even for first timers). Just make sure to soak all the nuts in penetrating oil for a while before. Any questions, we can help answer here.

 

1. You start with the furthest wheel in the system, and work your way closer. So, rear passenger, rear drivers, front passenger, front drivers.

2. As you bleed the main lines, the master cyllinder will be bled.

3. The bleed screw is all you need. You loosen it a bit, and the fluid will begin to run out, then you tighten it after the fact. This is true of both the front, and the rear.

4. You can use flare wrenches if it's a problem... But generally you can get a regular socket onto them too. Otherwise, you can take some vice-grips to them too... You might consider replacing them with speed-bleed bleed valves. They have a little check-ball in them, and enable quick one-person bleeding by eliminating the need to tighten, pump, release.

5. There are several ways you can go about actually bleeding it... If you want to do it quickly, you can loosen the valve, have her press the pedal once firmly, tighten the screw, have her release the brakes, rinse/repeat with occasional topping off of reservoir. You can get the speed-valves, and loosen all four at once, press the brakes, fill the reservoir, and repeat until only clear fluid comes out.

Or, you can do it the way I usually do, which is simply open one valve, and let gravity do its thing. The brakes will bleed themselves if you let them, it just takes a little longer. Just keep adding new fluid, and close up the bleeders once the fluid coming out turns from black to clear.

 

Thanks guys, that helps a lot. I'll take a look tomorrow and come back if I have any questions.

Also, while I've got you here, my e-brake doesn't work at all.. is the cable just hooked to the shoes and might need to be adjusted? I ran into this once on my Isuzu and it wasn't hard to fix.

 

Check the adjuster along the frame rail. Thought I had a pic but can't find it, should be on the outside after where the bed starts. Should be able to just tighten that in if the cables aren't trashed. I've done all my brake stuff, and still need to re-adjust that damn thing again...

 

I took off the vacuum hose at the brake booster, definitely has vacuum. Tried pressing the brake pedal while it was off and it didn't feel any different. Would this indicate that the booster is bad, or will I need to bleed the brakes first to check?

Also as far as bleeding the brakes, so it's not the 8mm nut but the much smaller one, right? The one that the tube goes on the end of.

I looked at the e-brake adjuster and only one of the brake cables is attached, the other one doesn't have the metal piece on the end of the cable.

 

Did you try to stop a moving vehicle with the booster disconnected? (I DO NOT reccomend doing so mind you) The pedal will feel the same weather the vacuum is hooked up or not, the only thing that effects brake pedal travel is the fluid, and the apparatus at either end there-of. But your stopping power would be decreased significantly without vacuum... Ever step on the brakes after your engine dies? It takes a bit longer, and a bit more pressure.

On the bleeding question... it should be the bleed-screw... The one that has a little hollow tube coming out of the middle of it. (Very, very short tube) They're usually 8-10 mil IIRC. This should be true of both the callipers, and the drum brake wheel cylinder. Will look something like this:

 

What are you talking about? There is a HUGE difference if the vacuum doesn't work. The pedal is ROCK HARD with no vacuum. You have to stomp hard and possibly stand on the pedal to work the brakes with no vacuum. The whole point of the booster, whether vacuum, or hydroboost, is to decrease the pedal effort required to adequately pressurize the brake system while stopping.

If its still squishy with no vacuum, then either there is a ton of air in the system, or the master cylinder is shot. Here is an easy test, after letting the truck sit overnight, with the engine off, try to step on the brake pedal. If it goes down easy, release and repeat a few times to let the vacuum bleed out. If you have to let the vacuum bleed out, wait a bit before continuing.. Then gently hold the pedal down with minimal pressure, it should feel hard and barely go down. Keep your foot on the pedal with the same pressure on it, and start the engine. If your vac pump is working, after a few seconds you'll literally feel the brake pedal start sinking away from your foot as the vacuum booster kicks in.

Back to the original question, I'd recommend putting a clear hose on the bleeder screw and dropping that into something like an empty water bottle. That way you can watch how much fluid (and air bubbles) come out and see how nasty the fluid actually is. You only need to loosen the screw enough for fluid to come out. Too loose and air can leak back in around the threads. Thats not a big deal if you are using a vacuum booster (they work well). Like someone posted above, my truck will gravity bleed fairly well, at the rears for sure. I usually use the vacuum bleeder as its faster. With two people its not a big deal. Loosen the screw, have her step, tighten screw, have her release pedal. Repeat until done.. The loosen and tighten there is only finger tight, just to keep air from sucking back in when the pedal comes up.

Also, you need to bleed the RABS unit after the rear brakes. Its will be on the drivers side frame rail near the front of the cab. There is a bleed screw on it just like the brakes have (and the picture above). If you have trouble loosening the bleed screws, let them soak in lube for a bit, try to clean out the hole in them and shoot some down there too. Use a 6 point medium, or deepwell socket with a small breaker bar to break them loose. If they round off, try vise grips. If they snap off, its probably time to replace the caliper/cylinder anyways... thats more involved than you want to do right now, so lets try to keep the work down to a minimum.

 

Then... why does my brake pedal feel the same when I push it in along with my clutch to start the car as when my car is running? o.o I know Fiero's are notorious for bad brakes, but shouldn't it be about the same weather it has vacuum or not? Unless you're actually trying to stop the car?

EDIT: holy crap you're right XD I guess my Fiero holds vacuum pretty well... Went out and pumped it a few times and it got hard... Well harder... it still wasn't like pressing my foot against a piece of steel or anything, but definitely felt much different. My bad!

 

Yeah, when my vacuum pump was causing my brakes to not function properly, the pedal itself was still basically the same. It's just you had to press it in all the way and hard to get braking.

 

Well after pumping the brakes a little it seemed like the pedal was pretty solid.. once I started the engine it definitely sunk down some underneath my foot. Should I proceed with bleeding the brakes then? Hopefully it's not my master cylinder!

 

Bleed the brakes no matter what. From the info given, I'm aiming at it being your booster.

Twilight Fenrir: Yes, there is a HUGE difference in pedal feel/stopping power if the booster isn't functioning. Longer stop distances because the driver is doing all the work to stop the truck. I had mine go out while driving, so I got the instant feel for the difference, haha.

tecgod13: The OP's truck is an 86, so no ABS.

 

Well you're right about not being able to stop as quick, hit my first yellow light yesterday and while I maybe could have pushed it and made it, I had enough time to stop safely but just barely, probably took me a good couple meters before I stopped! Luckily there wasn't anyone in front of me.

Do you think the brake booster will just need to be replaced then? I'll start shopping around, maybe I could find one from the junk yard here, or should I just go with a new one?

Good call on the no ABS system, I was actually going to ask if it's for sure on this year because I couldn't find it. It seems the bleeder screws on the back wheels are 1/4" and the front is 3/8" does this sound right? Will I need 2 different size tubes?