brakes

[BroncoJoe19]

Gentlemen:

There is so much that I do not know, and I have so little experience, that those of you who have both knowledge and experience far beyond my own that you could many times make me look foolish, but do not, I just want you both, and all, to know that I so greatly appreciate the fact that you guys go out of your way to support me, and to teach me, that which I do not know.

Thank you

joe

 

[shift1313]

no problem at all joe. If i know something im glad to share, but with these online forums sometimes its really hard to get the message across and especially do without stepping on anyones toes. This forum seems like a really good place, atleast the 80-96 bronco crowd

and Blade, i think those videos are great! I personally would love to see you rebuild a Tcase with one hand holding a camera /emoticons/[email protected] 2x" width="20" height="20" />

I actually thought about a photo archive of standard repairs like ball joints and things of that nature but i get pretty dirty when working on stuff and i doubt the wife would want to stand around and take pictures

the xvid codec seems to compress videos well. I took a 200+mb vid down to 12mb with it.

 

[BLADE262US]

Do you have a link to download that software Ill try it . LOL definately have to get a tripod for a vid on a T case rebuild the snap rings would be rough . /emoticons/[email protected] 2x" width="20" height="20" />

 

[ms_jetset]

Do you have a link to download that software Ill try it . LOL definately have to get a tripod for a vid on a T case rebuild the snap rings would be rough . /emoticons/[email protected] 2x" width="20" height="20" />

Keep up the great work guy's...this is getting very entertaining! /emoticons/[email protected] 2x" width="20" height="20" />

 

[shift1313]

blade, xvid.org should have the download for you. all of it is open source so there should be no fee's involved

snap rings, id like to see you un-bolt and seperate the two halfs with one hand. I swear all the ones i tear into are welded together by the previous owners.

 

[Billy Toppless]

I've got a 92 ford bronco, the problem I'm having is when you apply the brake pedal you get a pulsating, up and down movement in the pedal and shakes the front end. About 4 months ago i had to change the front rotors because one of the calipers locked up,so i replaced rotors and calipers and front wheel bearings. So I always thought a pulsating brake pedal was a warped rotor, so if anyone has any ideas what the problem is I would appreciate the help.

correct me if im wrong but if its in the pedal wouldnt it be from the rear?

it was my understanding that ud feel it more in the the steering wheel for the front wheels

could be wrong tho

 

[BLADE262US]

No any kind of warpage in the front rotors will be felt directly in the brake pedal . Your brake pedal is basically a hydraulic pump . When you push it the caliper ( hydraulic cylinder ) is pushed out to squeeze the pads against the rotor . If its warped the force it generates back against the caliper forces the piston back in and the pedal to raise up . If its warped bad enough you will get a shake in the front end that can be felt in the steering wheel as well . /emoticons/[email protected] 2x" width="20" height="20" />

 

[rogmit]

No any kind of warpage in the front rotors will be felt directly in the brake pedal . Your brake pedal is basically a hydraulic pump . When you push it the caliper ( hydraulic cylinder ) is pushed out to squeeze the pads against the rotor . If its warped the force it generates back against the caliper forces the piston back in and the pedal to raise up . If its warped bad enough you will get a shake in the front end that can be felt in the steering wheel as well . /emoticons/[email protected] 2x" width="20" height="20" />

 

[rogmit]

So, is it possible that the calipers are malfunctioning and causing the rotors to warp or would that be possible?

 

[BLADE262US]

It is possible that a caliper could hang up and cause excessive heat which would warp the rotor but it would also make the vehicle pull to the side of the hung up rotor /emoticons/[email protected] 2x" width="20" height="20" />

 

[shift1313]

early or late style calipers need anti seize on the caliper sliders. The older style have a slider pad with a spring. the later style have a set of rubberized(center) sliders. i believe these were designed this way reduce noise.

as blade said this would cause it to pull to one side or the other though.

also the vehicle in question is a 92 so it would have the RABS setup. the chance of any pulsation from the rear(if you could get the brake drum warped) would likely not make any noticeable impact on the pedal considering how brake shoes are setup, the distance and all the valving its traveling through. atleast ive never seen it happen.

warpage occurs from over heating and since your front brakes are about 75% of the stopping power they typically are the only sets to warp unless you have other issues with the rear brakes like a stock caliper or leaking wheel cylinder swelling brake shoes to cause improper wear.

 

[rogmit]

It is possible that a caliper could hang up and cause excessive heat which would warp the rotor but it would also make the vehicle pull to the side of the hung up rotor /emoticons/[email protected] 2x" width="20" height="20" />

 

[rogmit]

I was looking at the pads and it seemed that the inside pad was wearing thinner than the outside pad, is that normal?

 

[BLADE262US]

I guess that could be seen as normal it is the first one to come in contact with the rotor and if the caliper didnt release all the way it would probably have the most pressure against it . /emoticons/[email protected] 2x" width="20" height="20" />

 

[rogmit]

I guess that could be seen as normal it is the first one to come in contact with the rotor and if the caliper didnt release all the way it would probably have the most pressure against it . /emoticons/[email protected] 2x" width="20" height="20" />

 

[BroncoJoe19]

I was looking at the pads and it seemed that the inside pad was wearing thinner than the outside pad, is that normal?

I am far from the expert here, and am responding in part to get a better understanding from the guys who do know more.

I'm thinking that if the inner pad is wearing a little bit more, that might be normal, but if it is truely noticable, that *should* be abnormal. If I understand it correctly, the hydrolic cylinder in the caliper elongates and directly pushes the inner pad against the rotor. While elongating, the hydrolic cylinder in the caliper (which is like a great big fat heavy ugly C-CLamp) pushes against the inside of the caliper forcing it to squeeze the outside pad against the outside of the rotor. The moving part of the caliper is on two rods, and they are supposed to be lubricated (I guess with the anti sieze that Matt mentioned above). If they are not lubricated, AND the caliper doesn't move freely, THEN one may get uneven pressure on the rotors, both when engaged, and perhaps when disengaged. Uneven pressure would give uneven wear, and uneven heat. I imagine that uneven heat may give warping.

I might be all wet here, I'm not talking from much experience with disc brakes as I have only changed them once or twice in my life, but that's what makes sense to me.

 

[rogmit]

besides the rotor being warped, you don't think it could be the axle shafts do you, because if I have to pull this apart again, I'd like this to be the last time for pulling this apart, because I'm going to get wagner brake parts and something not made in China

 

[BLADE262US]

Nope wouldnt be anything to do with the axle shafts they just hang out inside the spindle which is bolted to the steering knuckle with 5 or 6 bolts . The hub assy sits on the spindle riding on your hub bearings . BroncoJoe you are mostly right on the caliper except up until around 94 they didnt ride on the 2 bolts that acted as pins for the caliper to slide on they fit in a groove on the steering knuckle and on the top and bttom there were these sort od pins that you drove in that consisted of two metal sides with a block of rubber in the middle kinda cheesy but thats what they were and pretty much held constant pressure on the caliper to stering knuckle which may be why they changed to the pin style . Anyway a caliper is like you said a big ugly C clamp its a metal frame with a hydraulic cylinder built in . The piston is made of chromed metal or the latter ones are a phenolic ( plastic ) type material . Your brake pedal is a pump and when you push it the piston in the caliper moves out but what makes it come back when you release the pedal ? The seal for the piston does its like an O ring but instead of it being round ( not round as in the shape of the piston but rather its diameter ) it is called a square cut o ring . It would be like a piece of 3/16 x 3/16 inch square rubber stuck together at the ends to form a circle in the diameter of the piston its sealing. If it were a true O ring the piston would go out and not release till forced back . Anyway the sqare cut oring flexes out as the piston moves and when the pressure is released the square straightening back out to its normal shape moves the piston back just a bit which relieves the tension on the brake pads . If you ever take one apart usually the nethod is to put a piece of wood infront of the piston them blow shop air into the brake line hole this will push the piston out but be careful not to have your fingers around the piston a 2 inch piston with 100 psi behind it will generate enough force to break almost every bone in your hand , wouldnt be good /emoticons/[email protected] 2x" width="20" height="20" />

 

[shift1313]

Nope wouldnt be anything to do with the axle shafts they just hang out inside the spindle which is bolted to the steering knuckle with 5 or 6 bolts . The hub assy sits on the spindle riding on your hub bearings . BroncoJoe you are mostly right on the caliper except up until around 94 they didnt ride on the 2 bolts that acted as pins for the caliper to slide on they fit in a groove on the steering knuckle and on the top and bttom there were these sort od pins that you drove in that consisted of two metal sides with a block of rubber in the middle kinda cheesy but thats what they were and pretty much held constant pressure on the caliper to stering knuckle which may be why they changed to the pin style . Anyway a caliper is like you said a big ugly C clamp its a metal frame with a hydraulic cylinder built in . The piston is made of chromed metal or the latter ones are a phenolic ( plastic ) type material . Your brake pedal is a pump and when you push it the piston in the caliper moves out but what makes it come back when you release the pedal ? The seal for the piston does its like an O ring but instead of it being round ( not round as in the shape of the piston but rather its diameter ) it is called a square cut o ring . It would be like a piece of 3/16 x 3/16 inch square rubber stuck together at the ends to form a circle in the diameter of the piston its sealing. If it were a true O ring the piston would go out and not release till forced back . Anyway the sqare cut oring flexes out as the piston moves and when the pressure is released the square straightening back out to its normal shape moves the piston back just a bit which relieves the tension on the brake pads . If you ever take one apart usually the nethod is to put a piece of wood infront of the piston them blow shop air into the brake line hole this will push the piston out but be careful not to have your fingers around the piston a 2 inch piston with 100 psi behind it will generate enough force to break almost every bone in your hand , wouldnt be good /emoticons/[email protected] 2x" width="20" height="20" />

Its fun on stuck calipers where there is a large gap between the wood. BANG!

Is the oring in the caliper really the only thing that helps the piston "ease off" the pads? I never really thought about it before but it makes sense. This is a motorcycle caliper but you can see the oring he is speaking of.

Blade, what year(in the 80s) did ford change the front calipers to the style you mentioned, rubberized pin. I know my 89 has that style but my 85 and 86 have the older style with the spring. Basically there was a step cut into the spindle that the bottom of the caliper rides on, and the top has a retainer and a spring which get hammered in place and a single bolt holds it. the spring raises the caliper up off of the step in the spindle. Info purely for my own reference

 

[BroncoJoe19]

Blade and Shift,

You guys are a great source of information, so with the explanation of how the caliper works, IF he is getting uneven wear of his pads, can he just **** up the caliper sliding mechanism, or does he have to, in the least, replace the square seal?

And what should he use for a lubricant?