What Brakes?

I am having some serious issues. When I try to slow and stop I get a horrible vibration.. grinding.. and only what I can describe as the sound of a train wreck on a small scale.

I am thinking.. (Since I swapped the odd rim out on the front) That I have 4 wheel drum

Autozone.com says I have front disc.

87 Comanche 6cyl 4x4

any help would be great.

Going to try to look tonight when I get home.. but it will be after 12 and rather dark.

Really????

You definitely have front discs. You have hit the end of the life of your pads. and by the sounds of it, one of your rotors as well. If it is a constant grind, then your caliper is seized. If it is only when you hit the brakes then get those brakes fixed before the caliper goes bad.

No comanche will have front drums unless it's been swapped on. I'd bet, if the sound is coming from the front, that you're grinding the pad rivets into the discs. Luckily the discs are dirt cheap, as well as the pads.

pads $15

disks $25

truck falling of jack sucks

brack rotor landing on your foot makes a really loud cracking sound

trust me not healed all the way yet 11 months later :???: :doh:

pads $15

disks $25

truck falling of jack sucks

brack rotor landing on your foot makes a really loud cracking sound

trust me not healed all the way yet 11 months later :???: :doh:

Last time I got pads they were $24 for all 4 and disks were 18 apiece.

Just the Jack?

Good Idea:

Bad Idea:

Bad Idea:

WTH!!!!!!! :eek: :eek: :eek: :eek: :eek:

Thats just plain STUPID...

:fool:

Yeah... welding next to a gas tank... Just Wrong.

Yeah... welding next to a gas tank... Just Wrong.

:rotfl2: :yes: :agree:

It would only be stupid if a welding spark gets him and he jerks back forgetting the prop was behind him and he knocks it out. See the shadow - he has a spotter - who doesn't want to be identified in the picture and is standing safely away in case something happens - some spotter! What cracks me up is he took the time to clean up all of the equipment to lift the truck, or his buddy is using that for his project. You wouldn't want all the blocks and jacks lying about, you might trip over them and fall and you thought he wasn't concerned about safety. A clean worksite is a safe worksite. He even chocked the wheel. Also notice the angle of the prop is such that it wouldn't slip where it hits the truck. He's really thinking here. You know how you are doing a short repair and then do something stupid and it turns into a much bigger job. He took precautions here. If the prop was square to the ground but angled to the truck and slipped out, it could possibly cause damage to the truck (or the prop)and that would have ruined his day because now he would have more work to do - if he survived that is.

^

Ripped into this last night..

Issue was just that..Inner pad on front right had worn down and was metal on rotor. Killed the rotor.

New parts:

Pads 15

Rotors 2 for 50

Brake cleaner and hand cleaner 5

tax 5

total 75

Now I have a new and fun issues..

Truck starts.. runs.. I go.. and I have no pedal till 80% of travel. I can pump it and build pressure but it doesn't hold

Idea's?

Also when I do hit the brakes I can slow it but there is a definite "POP" and the E-Brake light comes on.

I will reiterate I am a computer guy.. not a mechanic in any way. I do my stuff myself to save my $$$ but I loose my mind.

Ripped into this last night..

 

Issue was just that..Inner pad on front right had worn down and was metal on rotor. Killed the rotor.

 

New parts:

 

Pads 15

Rotors 2 for 50

Brake cleaner and hand cleaner 5

tax 5

total 75

 

Now I have a new and fun issues..

 

Truck starts.. runs.. I go.. and I have no pedal till 80% of travel. I can pump it and build pressure but it doesn't hold

 

Idea's?

 

Also when I do hit the brakes I can slow it but there is a definite "POP" and the E-Brake light comes on.

 

I will reiterate I am a computer guy.. not a mechanic in any way. I do my stuff myself to save my $$$ but I loose my mind.

Did you have the lines off at all? Sounds like possibly a bleeding issue...

I should have caught this before now... You need to double check where your pads set up against the knuckles.. If just one side of the pads are wearing then I'm willing to bet you have notches where the pads ride...

ok...

Your driving, then brake.. the pads are forced up into the knuckles where they ride, inside the caliper brackets. They wear the knuckle surface and make grooves in the knuckles. Those groves bind up the pads on one side causing extra pressure only on one side, mostly the outer side, but if the outer pads bind up then the inner side will wear.

When you take the calipers off you should feel the knuckles and make sure their flat, if they have grooves then take a grinder and make them smooth. Just had to do this on my XJ,, I was wondering why the inside rotors were wearing faster then the outside. It should be equal on both pads if everything is working right.. I had real bad grooves in my knuckles, and had to use a flap wheel to take them out and smooth up the surface..

If you don't then your pad life will be cut in half, and if you don't catch it then it will eat your rotors out on one side...

Any idea for the "No brakes" unless I pump them to build pressure?

Any idea for the "No brakes" unless I pump them to build pressure?

Did you have the lines off at all? Sounds like possibly a bleeding issue...No Pressure, poor pressure, could be air in lines...

Yea......

By chance......is the master full??

If not, then you might have a leak some where, hard lines, soft line, wheel cylinder. Check out all the lines for a leak, and repair as needed. Then you need to bleed the brakes.

If you heard a POP sound, you might have popped the equalizer, under the master. Bleed the brake lines, and the you need to apply about 250 pounds of force on the brake pedal to re-set the equalizer. And re-bleed the lines.

At worst case.......your master cylinder went south on you :( If you pedal needs to be pumped up for the brakes to grab, that's a sure sign that the master is shot.

Sounds like air in the system. If there is, make sure you bleed with the proper procedure if your still running the height sensing valve. A PITA but only way to bleed the air out..

I reread your post and missed the E-brake light on......that also means you have low pressure in the brakes, in the master cylinder. Another sign that theres a leak, or the master is gone.

This is the steps we took

Wheel off.

Pulled the 2 Allen head bolts

Slide the caliper off.

Took off the Rotar.

Took off inner pad

Popped the top off the master cylinder

Used the old pad (Really just the metal backing at this point) and a C Clamp to compress the Caliper piston. Had to take some fluid out of the Master Cylinder as not to overflow it.

Replaced the inner pad.

Put on new rotor.

replaced outter pad

Set Caliper in place and put back in the 2 Allen head bolts

Repeat on other side.

Never took the lines loose. I have checked the level in the master cylinder yesterday and it is full. I have checked for any leaks in lines and find none

I think it's a vacume issue. Going to look at a new master cylinder as well.

Okay, now I'll try to be serious and not sarcastic.

Something moved the brake failure plunger. Could have been a failure in the front or the rear. The 'pop' probably was when it moved and the light came on. You need to tell us if the truck is pure stock with the original hardware like the rear height sensing valve and the Comanche proportional valve where the brake failure switch is. If it is modified, who did it? Previous owner?

In the meantime pump the brakes and hold while someone checks to see if all wheels are locked. Does the pedal hold or does it leak down while you hold it? I suspect once you fixed the front brakes another failure showed up.

Until the brake failure switch is reset you don't know what the brake system is doing especially if it had been modified.

As far as I know and can tell all is stock.

From everything I can see/tell on it the Rear Height Snesing valve and the Proportional Valve are OEM and have not been modified.

I know that sitting still I can pump the brakes and they do hold. they do not leak or loose pressure. I will have to get it over to my dad's house this weekend to check if wheels move when brake's are applied (Live in an apt with little working space).

How do I "Reset" the brake failure switch?

Now this is what I have found when I drive in a empty lot.

get truck moving to about 20-25.. put the tranny in neutral. I press the brakes. Get response at 80% or so.. at 90% "POP" and the e-brake light comes on.

I bring the truck back up to speed. pump the brakes 3-4 times and apply with pedal at 40% of travel. The E-brake light goes out and I stop.

Sorry if I come off sarcastic.. really been a rough few weeks here. Just came from a funeral.

You don't have to reset the switch since it is still floating and sensing different pressures between front and rear as it should. The feel of the brakes with the brakes applied will tell you alot. You should be able to do it with one side off the ground and then try to rotate the wheels at your different pedal positions. That will tell you if the front or rear are working and when. I suspect you got some air into the rear emergency line. There is a procedure to bleed it and hopefully someone who has done it can jump in, but it could also be a failure of the master cylinder.

Sorry to hear about your funeral, but the sarcastic comment is for my earlier post about the picture of the truck on it's side. For everone's information, I was not serious. When you realize how little force there is on that prop with the truck at the angle, you'll know how dangerous it was.

Everything I read on your step-by step seams correct. The only possibility is when you removed fluid from the master, you might have contaminated the fluid :hmm: Or.......the fluid got to low, and is sucked some air into the system.

Also.......adjust the rear brakes before you start replacing any additional parts, the "self" adjuster are not self-adjusting :roll: and you will notice a big diffrence in the brakes with the rears also working properly.

You also write ..... . at 90% "POP" and the e-brake light comes on.

That's when your shuttling the by-pass in the differential valve, that's the popping noise you hear.

After you bleed the lines, and if you need to "re-set" the by-pass valve, that's when you need to apply about 250 pounds of force to the brake pedal to re-set it.

And......here's the procedure for bleeding the brakes with the hight proportioning valve in place, Posted by Mr. Eagle- (viewtopic.php?f=2&t=4917&hilit=rear+brake+bleading)

Quote:

After bleeding the brake calipers and cylinders the rear brake by-pass line must also be bled.

Open a front caliper bleed fitting and depress the brake pedal to the floor. This will shuttle the by-pass differential valve and allow fluid to flow through the by-pass line. The brake warning light on the instrument panel will illuminate when the ignition key is in the ON position. This signals the shuttling of the valve.

Re-Bleed the rear brake cylinders with the front caliper bleed fitting open.

After re-bleeding the rear brake cylinders the entire system must be bled again.

Bleed the brake calipers and cylinders in the following sequence:

1st -- Right rear

2nd -- Left rear

3rd -- Right front

4th -- Left front

Ok.. I have an idea.. I could be 100% wrong but?

I am thinking that when we "Recompressed" the Caliper Piston it caused something to go bad in the Combination Valve

I am basing this on the following image:

http://econtent.autozone.com:24999/znet ... pg/1.image

Now.. anyone know where/how to get a replacement one?

Swap to the newer double booster.. With new MC and XJ prop valve.. Delete the rear prop valve and line.