bad caliper or air in the lines?

[Tom]

Last night I replaced the front left caliper on my 79, and bleed all the brakes. Took it for test drive. It seemed like either the brakes were holding or the rims were still rubbing on the caliper bracket [my guess was #2]

So I went to drive it to the exaust shop today to have the exaust raised up. On the way I had several problems. #1- after braking, the steering wheel would pull to the left. It would stop after a while.
#2- when coming up to a stop sign, I hit the brakes. They went strait to the floor, and my brake light came on. I pumped em again, which gave me slight brakes, and I slammed the pedal down. I stoped just in time. After I released the pedal, the brakes wouldnt un-lock. I had to use a lot of gas pedal to get moving, and they gradually let go. I only went about 15ft before my next turn, and when I hit the brakes then they worked ok like before.

So, does this sound like air in the system? Would air cause one caliper to lock up like this? Thanks for any help.

[low 84]

damn, you got all kinds of problems. i would replace both calipers not just one. and i would check your hoses (frame to caliper) real good. how did you bleed the breaks? sounds like you might have air in the lines also.

[AirMale]

I agree......change both calipers and while your at it change both of the rubber brake lines. I had the same problem as you did once and it was because the rubber lines collapsed inside and restricted the the flow of the fluid.

[Tom]

I have $100 to last me all week. New lines and anothe caliper are not a option right now. I bleed the brakes with a one man bleeder. It filled up fine and didnt have any bubbles in the rubber tubing

[Captkaos]

I never had good luck with those vacuum bleeder ( call me old, old-fashion, whatever) but I would rather push the nasty old brake fluid out into a bottle of brake fluid so I can see the bubbles and put fresh fluid back in. It has always been a 2 person operation for me.

BTW, if you have old brake fluid, you might want to chunk it. Over time (even in a bottle) is will absorb moisture and go bad. Which is another reason for replacing brake fluid after a while.

Locked calipers most of the time are from a collapsed rubber hose. It could be rusty and sticking though. Mushy or no pedal is a symptom of air in the line.

[swervin ervin]

A sticking caliper will act the same way as a collapsing hose. Also, I've never had it happen, but heard of this. A piece of the rubber brake hose can flake off and act like a valve inside the hose. It will let the fluid go through to the caliper, but when the pedal is released, the rubber flake will plug the hole and slow down the fluid flow.

Depending on how old the hoses are, I would think this is the problem. I know how it is to be tight on money, but is it worth maybe wrecking the truck, when your brakes fail?

Brakes are something you never take lightly, when not working right. Never, ever, drive a vehicle with bad brakes.

[Tom]

Dont worry guys, I wasent going to drive it in this condition. The only reason it got driven this morning is because I had to have the exaust moved in oder to drive this weekend, it was a mile away.

The hoses do look old. I found somthing tonight that might be the problem. BOTH hoses look kinked and bent badly againts the top spindle nut. The hose turns to solid tubing right after this point, so I dont see how I can get around it. Anyone else have this problem? How should I correct it? Im going to buy new brake lines tonight. Ill borrow money from my parents if need be.

I tried bleeding the brakes again, with my brother pushing the pedal and me watching with the bottle. The left side [the one not releasing] had fluid come out quickly and fine. The passenger side on the other hand had difficulty getting fluid out. If my brother didnt push the pedal completly down, no fluid would come out. Hope this is enough info.....

[swervin ervin]

Sounds like to me instead of something wrong with the side you worked on, it's the other side, not working right. By fluid not wanting to come out, leads me to believe it's a bad hose or maybe a bent metal line.

[72MARIO]

Your master Cyl ,Dude there is proibly tons of crap in the bottom. stopping the fluid from going too the brake calpier.

[low 84]

i agree with chris the two man way is what works for me. i've even had to get my mom to 'man' the peddle while i bleed. are you using this method: 1. pour small amount of fluid in the bottum of your bottle (20 oz coke bottle works good) 2.connect hose to bleeder screw and run in to the bottle, and submerse in the fluid in the bottle so you can see bubbles. 3. have peddle man pump peddle a few times then hold as far down as possible. 4. open bleeder valve and let pressure out. 5. close bleeder screw. 6. have peddle man release peddle 7. repeat 3-6 as many times as needed.

aslo i do it starting from the break thats the furtest away from the master cylinder working towards the nearest, so RR, LR, RF, LF.

and also while your bleeding periodically check master cylinder level b/c if it runs dry then you gotta start from scratch.

i'm sure you know this stuff, but just incase you forgot something

[Tom]

Well, progress had been made. I moved [read: bent] both metal lines so the rubber part isent smashed by the spindle nut. This released the pressure for both calipers. I then recruited my little bro again

I started with RR, then LR, RF, LF. This time I got more air bubbles out. The fluid moved great. I didnt have him pump the pedal before I opened the bleeder valve though. I just put the tube over the screw[with fluid in the bottle already] and opened it, then had him pump the pedal. Is this in-correct? Anyways I went to test drive the truck again [with shock extenders installed finally] and I had almost no brakes at all. I didnt even try getting out of the driveway. Im getting a bigger bottle and trying again tomorrow. Thanks for all the help guys.

P.S.- Im also replacing the fluid and checking to make sure there isent any junk in the master cylender

[low 84]

i never let the peddle up when the bleeder screw is open. i think mabey if you let the peddle up while the screw is still open then it will suck air right back up the line. i'm not sure on this but i've always done it with pumping, then open, then close, the release peddle. this how i help the mechanics at work do it too. i'm have to be the peddle man at work sometimes

[Tom]

Originally posted by low 84
i never let the peddle up when the bleeder screw is open. i think mabey if you let the peddle up while the screw is still open then it will suck air right back up the line.

Thats why they invented a one man bleeder bottle When you release the pedal, the sucktion in the tube [which is at the bottem of the bottle which already has some fluid in it] pulls fluid back instead of air, so you can leave the valve open while you pump the brakes.

[86SILVERADO]

Low 84 is right. I find myself having to bleed the brakes by myself all the time for some reason. It sounds like you pretty much got it down Tom but just to sum it up. Start with the rear like you did crack bleeder screw and pump brake 6 or 8 times this should be plenty to get all air out of that line. On last pump down wedge a piece of 2 x 4 between pedal and the floor or the seat and go back and tighten the screw. If you let the pedal up it will suck air back into the system. This is how I always do it and it works every time. One other thing is there evidence of any seepage on the brake booster or against the firewall (brakes without vacuum assist) It sounds to me like the seal in the master cylinder might be shot. Also 72 Mario has a good piont. It never hurts to remove master cylinder and clean it out entirely. You can also get a good look at the seal in the rear of it this way. If there is evidence of any seepage you need a new one. Another long shot but you could have a metal line that has rusted through some where out of sight. Look for evidence of brake fluid else where on frame or underneath truck while you are bleeding the system.
Good luck, and like Mike said you don't want to mess around with brakes.

Sorry I just noticed that you are in arizona Most likely not the rust hole in the brake line problem. In your climate it will most likely be the rubber. Check master cylinder seal rear wheel cylinders and caliper piston seals.

Norris

[swervin ervin]

Well, to bleed brakes, I use one of these kits.



Works like a charm. It's good for a lot of stuff besides bleeding brakes too. Works real good to change out the old fluid too. I got tired of asking the wife to help me and then have to hear her complain. Yes, I've got wife that hates this stuff. Reason is her Dad used to own a junkyard. Enough said I guess.

[86k10]

A lot of good advice here, except i'm trying to figure out the use for the bottle. Oh I know, you guys are not like me and make a mess when you do this. I can understand that, most of the time I just let the floor catch it cause you never reuse fluid that has been bled out of a system. And brake systems should be totally flushed and the fluid changed every 3-4 years cause of the condensation that gets in it. That's why the fluid turns from the nice clear to an ugly dark color. That's where a power bleeder comes in handy, you can just open the bleeder screws and let it run until it's clear.



86K10 (Now K20)
455 Olds Rocket ( A little more power than the stock 305)
700R4 Trans (220,000 miles and still going)
208 Transfer Case
1969 Eaton 10.5 Rear Axle (No spin) 4.10 Ratio
8.5 Corporate 10 Bolt Front, Factory Limited Slip

[PHOENIX]

I need to flush my lines. Plus my master cyclinder is leaking where it attaches to the booster. I might replace it this weekend. I should flush the lines out then. I have never done it in the 6.5years I have had this truck (flush the entire system that is). Im sure it needs it bad!!!

EDIT:
I agree with Mike on that tool. My dad has the same one, if you go buy it make sure you get the metal one, the plastic wont last as long. Anyway its great for brakes and setting the carb (vacuum). I need to get me one of my own, real soon.

[82 Silverado 4X]

Phoenix
Brake fluid will ruin the rubber diaphram in the power brake booster if the master cylinder has a fluid leak. Be sure to check this out when you remove the master cylinder. You don't want to have to pull the new master cylinder off again to replace the booster later.

[PHOENIX]

Thank you, Ill be sure to check that. Is it just right there inside? It is easy to reaplce if needed?

[82 Silverado 4X]

I would pull off the booster and see how much, if any fluid, got inside after you pull the master cylinder. If it does have fluid inside and you have noticed the master cylinder has been leaking for sometime "I" would just replace the booster now. (I hate to do things twice) If it's just a recent seepage and you can't see any fluid go ahead with the master cylinder install and see how it works out.
Also I've had my "metal" vacume pump for almost 8 years. It's seen many a brake bleeds and I've never had a problem with it. I just used to to set up my Q-Jet a few weeks ago and still works perfect.

[82 Silverado 4X]

Sorry, Four nuts on the backside hold the booster on the firewall. There is also a pin with a clip on your brake pedal for the rod.

[79BIG10]

Eddie- I just did mine not too long ago. It's a b*tch to get the nuts off. Make sure to compare the rod length of new to old. Plus you can legthen the rod by unscrewing to have brakes come on faster.

[Captkaos]

Originally posted by 86k10
A lot of good advice here, except i'm trying to figure out the use for the bottle.

Since the hose is submerged, it is a failsafe just in case your assistant lets up some before you get the screw closed and pulls air back up into the system.

[86k10]

Yeh that would be a good idea, but I'm a farm boy and sometimes we don't think that far ahead.