After 4 years I think I finally found my problem.

Zymurgy

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I did the 73 disc brake conversion on Goldie, my '66 300. Everything that could go wrong seemed to go wrong. Even with a reoccurring irritating issue, I never regretted the conversion because it can stop on a dime now.

The very irritating problem is the front right caliper would grab after you would drive 15-20 miles, at the end of last summer it would happen after 5. I replaced the rubber hoses (which were replaced 4 years ago) but for a 73 they were too short so I got slightly longer ones. Thought my problem was solved but now back to the 15-20miles.

I decided to replace the caliper haven't seen any available for the last 2 years, Found one but now after a month and a half, I think the inventory was incorrect. I decided to remove and check out and clean the caliper pins. First one dirty a little rust, second was bent and had a couple of raised notches. This has to be my problem, Finally!

I started thinking about all the issues I had, and I suddenly remembered one of the caliper mounting bolts fell out while driving and the car came to a violent stop. That was 4 years ago and I presume that has been my main issue this whole time.

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Zymurgy

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That would sure cause things to hang up. Do you know a local machinist? Maybe have one made.
I called my buddy he had 4 pins, but said mine was in better shape than any of his. Fortunately I found a couple new at NAPA, still looking for a caliper, but don't really think I need it now.
 

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I called my buddy he had 4 pins, but said mine was in better shape than any of his. Fortunately I found a couple new at NAPA, still looking for a caliper, but don't really think I need it now.

Geeze. . . I remember all the consternation you had with yer brakes. Really glad you found the problem. Regarding the caliper: I'm pretty sure you can get a rebuild kit for it.
 

Zymurgy

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Geeze. . . I remember all the consternation you had with yer brakes. Really glad you found the problem. Regarding the caliper: I'm pretty sure you can get a rebuild kit for it.
I did see the rebuild kits out there. That was kind up my next question, is it pretty straightforward, any special tools needed?
 

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I did mine with a cheap drill mounted hone from RA. They came out great. The pistons are available too but mine cleaned up with some 0000 steel wool. I have a spare set of pistons if you can't find them elsewhere.

Yes! Easy to rebuild. Just a couple of o-ring seals, and new pistons are pretty cheap.
 

Ross Wooldridge

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How would the pin cause the caliper to bind up? Is it because after it gets hot the pin binds in the bore of the caliper and prevents the caliper from releasing after clamping?
 

Zymurgy

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How would the pin cause the caliper to bind up? Is it because after it gets hot the pin binds in the bore of the caliper and prevents the caliper from releasing after clamping?
I honestly think the those pads may drag slightly and over a period of time, because of the bad pin and eventually heats up the rotor. The bent and burred pin isn't allowing a smooth release either. Sometimes I could tap the brakes a couple of times when I can feel that caliper grabbing, and it would straighten up.
 

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Use a vice and try to straighten it. Use fine sandpaper to smooth it out and then try to polish it. I've done something similar on my jeep and it worked just fine. Be very careful trying to bend it back....
 

Zymurgy

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Use a vice and try to straighten it. Use fine sandpaper to smooth it out and then try to polish it. I've done something similar on my jeep and it worked just fine. Be very careful trying to bend it back....
I actually tapped it a few times with a hammer and got it darn close. I filed the burrs and then took some sandpaper to it.

I am driving it to the Mopar National this weekend, about 50 miles. I believe it is still in better shape than the last 4 years I drove there
 

Zymurgy

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FYI the caliper hardware for these calipers are the same as 1973 Dodge Challenger for calipers. See @ayilar post @Introducing a my 70 TNT convertible.
Thanks great information I was wondering if they may be the same on another mopar.
 

thrashingcows

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FYI the caliper hardware for these calipers are the same as 1973 Dodge Challenger for calipers. See @ayilar post @Introducing a my 70 TNT convertible.

I'm a tich skeptical of this statement, while they do have the same design the C-body stuff is just slightly larger and I think the corresponding pins are just a bit longer then the B/E body set-ups....but I could be wrong. ;)
 

david hill

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I'm a tich skeptical of this statement, while they do have the same design the C-body stuff is just slightly larger and I think the corresponding pins are just a bit longer then the B/E body set-ups....but I could be wrong. ;)
Here you are. The guide pins are identical in length. The caliper to the left is a 1973 Challender while the caliper to the right is a 70 Chrysler 300. The Challenger guidepins are shown installed in photo #3

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DSC04273.JPG


DSC04277.JPG
 

thrashingcows

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@david hill ...Thank you for the pics, but did you get those mixed on the left and right?? C-body calipers are slightly larger then the B/E body units and by the pics it appears the old crusty one is a C-body unit while the shiny new looking unit I would say is a B/E body unit.

I went through this issue many years ago when I did the 73 C-body disc conversion on my 68 T/C wagon, I ordered LH and RH calipers but the LH side caliper wouldn't fit right....messed around it for a while and finally figured out what the problem was, the caliper was slightly smaller then the RH unit. Returned it and got a correct C-body caliper and all was well.
 

david hill

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@david hill ...Thank you for the pics, but did you get those mixed on the left and right?? C-body calipers are slightly larger then the B/E body units and by the pics it appears the old crusty one is a C-body unit while the shiny new looking unit I would say is a B/E body unit.

I went through this issue many years ago when I did the 73 C-body disc conversion on my 68 T/C wagon, I ordered LH and RH calipers but the LH side caliper wouldn't fit right....messed around it for a while and finally figured out what the problem was, the caliper was slightly smaller then the RH unit. Returned it and got a correct C-body caliper and all was well.
If you look at the bleeder screws both calipers are from the side. The actual mechanics and dimensions of the seals, caliper piston, Caliper pin hardware and dust boot are the same. I used the Challenger Calipers as a doner for seals, pistons and mounting hardware for the 70 300 calipers.

DSC04277.JPG
 
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