Front disc problems
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Lead Driver
Joined: Mar 2008
Posts: 7,165
Likes: 375
From: Near Los Angeles
Front disc problems
Hey guys. I have a 75 f250 with dual piston calipers up front. I noticed I didn't have much lining on my pads so I changed them. (Disappointed to find that the Raybestos pads I ordered showed rivets holding pads to backing, but came with the lining material filling the voids once occupied by the rivets, as though lining is cast onto backing plate!) Anyway, I clamped the pistons into the calipers on the truck, bolted the pads in place, and away I went.
I did notice that the rotors had deep grooves, but they've been like that forever. There was not an issue with the old pads.
With the new pads the right side pads drag and make a crunching kind of sound when I brake. I'm thinking the rotors need to be turned or replaced, and the calipers could use a rebuild since it's been 8+ years since that was done. I've had the truck since ...96, and the rotors have never been turned.
I'm curious as to why it was fine with the thin pads, and now why only one side is a problem.
I did notice that the rotors had deep grooves, but they've been like that forever. There was not an issue with the old pads.
With the new pads the right side pads drag and make a crunching kind of sound when I brake. I'm thinking the rotors need to be turned or replaced, and the calipers could use a rebuild since it's been 8+ years since that was done. I've had the truck since ...96, and the rotors have never been turned.
I'm curious as to why it was fine with the thin pads, and now why only one side is a problem.
Senior User
Joined: Aug 2004
Posts: 394
Likes: 1
From: Nashville
It's possible the caliper pistons are rusted where they were outside of the quad seal, and when you pressed em back in the rust bound the pistons up in the quad seal where they can't retract. Also possible that the hose has failed internally, but not likely since it wasn't a problem prior to the pad replacement. I suspect the noise is related the the caliper sticking. First thing I like to check in a situation like that, I jack up the offending wheel, see how much resistance there is to turning the rotor, then crack the bleeder. If the resistance goes away, its the hose. If the resistance remains, its the caliper.
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Lead Driver
Joined: Mar 2008
Posts: 7,165
Likes: 375
From: Near Los Angeles
The hoses were changed 6 months back. Today I should be able to dig into the problem. I have a rebuild kit for the calipers. I guess it's time for me to rebuild them. It is nearly impossible to find replacements for the rubber rings that the mounting bolts ride in. Oh well ...
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
1975 F250 The hoses were changed 6 months back. Today I should be able to dig into the problem. I have a rebuild kit for the calipers. I guess it's time for me to rebuild them.
It is nearly impossible to find replacements for the rubber rings
that the mounting bolts ride in. Oh well ...
It is nearly impossible to find replacements for the rubber rings
that the mounting bolts ride in. Oh well ...1972 F250 2WD & F350 from serial number M80,001 // 1973/75 F250 2WD & F350.
GREEN SALES CO. in Cincinnati OH has 2 = 800-543-4959.
CARPENTER NOS OBSOLETE PARTS in Concord NC has 31 = 800-476-9653.
See 2B517 in pic:
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Lead Driver
Joined: Mar 2008
Posts: 7,165
Likes: 375
From: Near Los Angeles
Well I had another crack at the front right caliper--the one that was dragging. I removed the caliper and rebuilt it, cleaned off the pistons (dual) with 1000 grit sand paper. One piston was locked. I had to heat it, melt the seal, to remove it. I also had to remove and clean with emery cloth the slider pins/bolts. I also found that I had a spare set of front hoses, so I threw those on too.
I see that Rock Auto has the hardware kit with the rubber bushings that the slide/bolts/pins ride on. They also have the pistons, seals, pins, etc. They sell the rotors for half what the parts houses sell them for, and charge only $18 shipping. That's a savings of $50 each.
It is now all working peachy keene.
I see that Rock Auto has the hardware kit with the rubber bushings that the slide/bolts/pins ride on. They also have the pistons, seals, pins, etc. They sell the rotors for half what the parts houses sell them for, and charge only $18 shipping. That's a savings of $50 each.
It is now all working peachy keene.
Fleet Mechanic
Joined: Jul 2017
Posts: 1,448
Likes: 163
From: East Texas
Good job on getting it fixed.
Back in the day (88-90) I used to rebuild the rear cylinders on my 75. This time my son and I figured we would just get new (cylinders and calipers) and use the time saved on other repairs. Sometimes I think we undervalue our time on some repairs.
Back in the day (88-90) I used to rebuild the rear cylinders on my 75. This time my son and I figured we would just get new (cylinders and calipers) and use the time saved on other repairs. Sometimes I think we undervalue our time on some repairs.
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Lead Driver
Joined: Mar 2008
Posts: 7,165
Likes: 375
From: Near Los Angeles
I can see that in the near future I'll need to get the hardware kit, as well as new pistons, pins/bolts. These only lasted 40+ years.
I was surprised to see that there are phenolic pistons available as replacements. That was surprising. Give me good solid stainless in this case!
I was surprised to see that there are phenolic pistons available as replacements. That was surprising. Give me good solid stainless in this case!
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Lead Driver
Joined: Jul 2017
Posts: 9,545
Likes: 1,156
From: San Jose, CA
Yep, I still prefer steel in this application. But the phenolic models were there primarily (I think?) to get rid of the chance of rusting and sticking in the bore. But then some early ones got hot and cocked off at an angle or warped, so not such a great idea.
But if they're still using them, I guess they've over come the usual early shortcomings. Hopefully...
But I still like steel.
Paul
But if they're still using them, I guess they've over come the usual early shortcomings. Hopefully...
But I still like steel.
Paul
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Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,165
Likes: 375
From: Near Los Angeles
Good job on getting it fixed.
Back in the day (88-90) I used to rebuild the rear cylinders on my 75. This time my son and I figured we would just get new (cylinders and calipers) and use the time saved on other repairs. Sometimes I think we undervalue our time on some repairs.
Back in the day (88-90) I used to rebuild the rear cylinders on my 75. This time my son and I figured we would just get new (cylinders and calipers) and use the time saved on other repairs. Sometimes I think we undervalue our time on some repairs.
I used a phenolic carb spacer for a while. It cracked and broke. I would not want to risk that with caliper pistons. That is scary imo.
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