KH question

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4spdragtop

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A quick question( there'll be more I'm sure). How flat does the "ledge" have to be where the clips and pads go on KH disc brakes?
I'm almost ready(still need clips) to assemble these back together, but I read on "Slackers guide" that they should be flat?
I dont want to take off "too much"
Thanks all.

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Am I seeing where old pads have rusted to the flat surface? That where they need to be able to slide.
They have to slide , that might cause a click sound upon braking. I think the pressure will overcome sticking.
Can you weld and or file that flat?
 
File that surface down to get rid of the "divots"
I use one of these files, about 3/8 inch, square, in my rebuilding of those calipers.
I have seen, done, worse ones, that what your picturing.
Don't worry about filing too much, nothing bad is going to happen.

MAC File 001 (Small).JPG


KH Calipers 65-72 001 (Small).JPG
 
Thanks guys! I read on Scotts thread where he took your advice Jim and filed his down. My concern was "too much" filing.
MO, when you say "stuck pads" are you talking the outer circumference of the piston bore? If so, that area has some flash rust after sitting in and coming out of Evaporust.
Thanks guys, sorry pics are lousy, hard to get close up of the proper area.
Oh couple more questions, what's so special about "caliper paint"? I was going to use Duplicolor engine enamel. Its high heat so shouldn't it be ok to use?
Also got new pistons. Bore/diameter is identical to old ones, but height is shorter on new ones approx 0.08" Foreseeable issues?

Cheers
Steve
Am I seeing where old pads have rusted to the flat surface? That where they need to be able to slide.
They have to slide , that might cause a click sound upon braking. I think the pressure will overcome sticking.
Can you weld and or file that flat?

File that surface down to get rid of the "divots"
I use one of these files, about 3/8 inch, square, in my rebuilding of those calipers.
I have seen, done, worse ones, that what your picturing.
Don't worry about filing too much, nothing bad is going to happen.

View attachment 1715359780

View attachment 1715359786

20190703_225728.jpg
 
Don't worry about the height difference in pistons.
When they will be in normal use, they just will never see the very bottom of the caliper bore, that's all.

Form me, i never gave a darn what can of paint that i bought at Lowes or the hardware store.
Krylon, or Rust-Oleum is as good as anything that your going to use.
Those calipers are never going to get that hot to bubble the paint off them.
 
Theoretically, the paint should be hi-temp. I have used regular paint and it seems to hold up OK.
 
I always have a can of Duplicolor "cast iron" engine paint in the shop, I figgered it would be good enough.
**edit** thanks on piston height as well!
Thanks guys
Don't worry about the height difference in pistons.
When they will be in normal use, they just will never see the very bottom of the caliper bore, that's all.

Form me, i never gave a darn what can of paint that i bought at Lowes or the hardware store.
Krylon, or Rust-Oleum is as good as anything that your going to use.
Those calipers are never going to get that hot to bubble the paint off them.

Theoretically, the paint should be hi-temp. I have used regular paint and it seems to hold up OK.
 
i filed the rails on my KH callipers smooth and after some use the pads rattle on rough roads.I'm wondering if the little springs are not making enough contact now.Been so busy i haven't looked into it yet.
What are your thoughts hemi71x. Maybe this will help 4spdragtop
 
Thanks for posting ir3333. Good point.
When I was filing down the rails lightly I got to " fresh metal" but there are still divots.(I'll post better pics tomorrow)
I haven't measured but some are approx 1/8" deep. That seems like a lot. I dont have clips to check the fit yet as my thick skull forgot to order when I ordered pistons and seals.
I'll post pics tomorrow
Thanks all
i filed the rails on my KH callipers smooth and after some use the pads rattle on rough roads.I'm wondering if the little springs are not making enough contact now.Been so busy i haven't looked into it yet.
What are your thoughts hemi71x. Maybe this will help 4spdragtop
 
Just be sure the divots don't have square edges but have "ramps" so it will slide and not catch. You should be able to increase the clip retainers tension if needed so it won't rattle.
 
Thanks for posting ir3333. Good point.
When I was filing down the rails lightly I got to " fresh metal" but there are still divots.(I'll post better pics tomorrow)
I haven't measured but some are approx 1/8" deep. That seems like a lot. I dont have clips to check the fit yet as my thick skull forgot to order when I ordered pistons and seals.
I'll post pics tomorrow
Thanks all
Boy, if you have divot's that deep on the caliper "ways" where the pad sets down, you probably don't have any choice but to have them welded up, and file everything smooth.
Sounds like you have some really worn caliper body's.
Those pad retainer clips are designed to keep the pads from coming out the top of the rotor, and i don't know about this "rattle" over a rough road.
To the op.
If your buying Centric pad hold down clips, then in my experience they have to be bent down somewhat for proper usage.
You can easily figure it out when you set pads down into the caliper.

65-72 A Body Disc Brakes #7 011 (Copy).JPG
 
These calipers get pretty expensive to rebuild, don't they, when you find out that you need.
1 to 8 pistons.
2 rebuild kits
Caliper hard lines.
Caliper hard line bracket(s) if they weren't there
New rubber brake hoses
Pads
Pad hold down clips
Can of paint
Assembly lube, if you don't already have something
And whatever you feel your labor time is worth to you, in dis assembling them, cleaning them, painting them, then the re assembly.
Then if you have to pay somebody to weld up the divots in the caliper body.
Adds up quick. Lotsa $$$$$$$$$$$$ out of the wallet.
 
Tx hemi"...I haven't had a chance to take the wheels off to check for the cause of the rattle yet so i am not sure what is causing it.
You are right about rebuilding costs though.
 
Thanks for replies, here are some pics. Easier to see the divots with a few minutes of filing on them. I tried measuring, best I can tell is approx 0.050" on the deepest.
Yes Jim, they do start to add up in price. I needed 8 new pistons and seals, but had never tackled a rebuild on these, so the challenge is/was on.
Thanks all.
Boy, if you have divot's that deep on the caliper "ways" where the pad sets down, you probably don't have any choice but to have them welded up, and file everything smooth.
Sounds like you have some really worn caliper body's.
Those pad retainer clips are designed to keep the pads from coming out the top of the rotor, and i don't know about this "rattle" over a rough road.
To the op.
If your buying Centric pad hold down clips, then in my experience they have to be bent down somewhat for proper usage.
You can easily figure it out when you set pads down into the caliper.

View attachment 1715360037

Tx hemi"...I haven't had a chance to take the wheels off to check for the cause of the rattle yet so i am not sure what is causing it.
You are right about rebuilding costs though.

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Wow, your too far into them now, money wise, time wise, to give up on them now.
Those are bad, i didn't have a clue, even from the previous picture.

Not in person, but those are the worst ones that i have ever seen, in the literally dozens of them that i have rebuilt through the decades.

What's your decision now?
Find a welder?
Or cut your loses, and turn them in as cores?

I know you know, that those calipers are basically out of stock, over at Rock Auto, and that i currently have a pair of them for sale, here on this forum, that's for sale, at the price that i need to get for them, as a side line business.
And then, it would cost you another one hundred dollar bill, to get them to you, in Canada.
 
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Pics from yesterday kinda clouded the divots. Can see them pretty clear now.
Yeah that's partly the reason I got new pistons is that I saw stock dwindling so get them while i could. This set is for the 69(life long project) 67 has factory disc too, so they wont go to "waste".
I have a mig welder, but not very good at it lol. Hopefully good enough to "fill" the divots.
I'll see how good my welding skills are lol.
The hub to spindle bolts and caliper to spindle bolts, anything "special" or would grade 8 with proper dimensions work? I'm missing those.
Thanks again.

Wow, your too far into them now, money wise, time wise, to give up on them now.
Those are bad, i didn't have a clue, even from the previous picture.

Not in person, but those are the worst ones that i have ever seen, in the literally dozens of them that i have rebuilt through the decades.

What's your decision now?
Find a welder?
Or cut your loses, and turn them in as cores?

I know you know, that those calipers are basically out of stock, over at Rock Auto, and that i currently have a pair of them for sale, here on this forum, that's for sale, at the price that i need to get for them, as a side line business.
And then, it would cost you another one hundred dollar bill, to get them to you, in Canada.
 
Steve, Thems cast iron. IMO not something to MIG.
Possibly could be brazed with a wear resistant filler rod.
To weld they need be heat soaked. Oven is best, heat table will work.
Then welded. then slowly cooled in the oven or on the table or whatever.

Another option might be tacking down shim stock. I'd even consider using an epoxy made for steel to hold the shim down. The ears of the pad backing plate will trap the shim. Only place they could really move is sideways.
 
I once had my welder, machinist, friend of mine, weld up the divots in a pair of caliper bodies that i was determined to save.
Don't know what material that he used, or what process, but the "weld" material was so hard, a file wouldn't touch it.
Got out the Dremel with a carbide bit, and that did the trick.
 
Get using any 'epoxy' JB Weld, out of your mind.
Nothing like that is going to work on that wear area on those calipers.
Whatever process a skilled "welder" uses, will get the job done.
I had some done in the past, they are do able, or just boat anchors, if you don't want to fix them up.
 
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What I was suggesting was shim stock as the running surface and the epoxy as the filler and adhesive beneath.
Actually better than shim stock would be some Brown & Sharpe. Cut and fit it, then harden it.
Look it up as oil hardening or water hardening steel.

Cut it something like the dashed lines and it will be mechanically trapped once installed.
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But don't give up on welding or brazing just yet. Call and make some visits.
When I needed a exhaust manifold welded down here, it took a little hunting to find the right guy.
One place wanted more than I thought was fair price and another shop, different location, was super reasonable. I think part of it was location and part of it was he could just slip that job in amongst the other jobs he was doing. Different overhead and different type of operation. Both places could do the work equally well IMO.

There's some good welders here who can prob advise if brazing is an option for filling and resurfacing here. @Sublime one
 
Geez, people, windowed engine blocks get repaired, and used again, and who cares what method gets used in filling up those divots in those caliper halves.
At this point, who cares if you call it weld, braze, mig, tig, fig, big, or anything else.
To the op.
Get them filled up, or junk them.
Know you don't like to hear that, but if you had to do this all over again, from the start, you decision probably would be lots different with them, before you started spending all your money, on all the rebuild parts.
My .02 cents worth on the subject.
 
JB...get it perfectly smooth and keep it covered with disc brake silicon grease?
Epoxy with graphite power becomes rock hard?
welding would be best...
 
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