brake caliper slide pin alignment trouble

[weq92f]

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Anybody else here have to grind on either the caliper bracket, the caliper or both to make the slide pins line up with their resting spot on the outboard caliper ear, top and bottom?

Went to re-seal my existing calipers and found the cylinder walls pitted on both. Bought two new at local store. Passenger went on fine but driver doesn't.

I'm running ECE drop spindles and stock 72-87 rotors/calipers. If I wedge a crow bar in there, I can twist things into place but at that point the caliper is rigidly mounted and will not float on the pins.

I purchased a second "new" caliper from a different parts house and it has the same alignment issue.

Found an old thread here where a member did do some grinding...just curious if this is a common issue.

https://67-72chevytrucks.com/vboard/...d.php?t=568682

Thanks,

-Kevin

[RustyPile]

Originally Posted by weq92f

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Anybody else here have to grind on either the caliper bracket, the caliper or both to make the slide pins line up with their resting spot on the outboard caliper ear, top and bottom?

Went to re-seal my existing calipers and found the cylinder walls pitted on both. Bought two new at local store. Passenger went on fine but driver doesn't.

I'm running ECE drop spindles and stock 72-87 rotors/calipers. If I wedge a crow bar in there, I can twist things into place but at that point the caliper is rigidly mounted and will not float on the pins.

I purchased a second "new" caliper from a different parts house and it has the same alignment issue.

Found an old thread here where a member did do some grinding...just curious if this is a common issue.

https://67-72chevytrucks.com/vboard/...d.php?t=568682

Thanks,

-Kevin

Let's use sone common sense reasoning here.. If the original caliper fit the spindle as it should, it stands to reason any proper replacement caliper should also fit. No grinding should be necessary. Use another supplier for the caliper source.. If you grind on the spindle, you'll be permanently damaging it and nothing will fit.

[weq92f]

Originally Posted by RustyPile

Let's use sone common sense reasoning here.. If the original caliper fit the spindle as it should, it stands to reason any proper replacement caliper should also fit. No grinding should be necessary. Use another supplier for the caliper source.. If you grind on the spindle, you'll be permanently damaging it and nothing will fit.

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I agree. However I have no idea whether the caliper I removed had been modified to fit these spindles. The core is gone to another remanufacturer so I can't compare old vs. new.

-Kevin

[RustyPile]

Originally Posted by weq92f

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I agree. However I have no idea whether the caliper I removed had been modified to fit these spindles. The core is gone to another remanufacturer so I can't compare old vs. new.

-Kevin

Under any event, grinding and modifying brake components in order to "force fit" is never an option. Just because someone else took those steps does not mean it's the proper approach. Safety cannot be compromised..

The following is not meant to be a solution to the problem, only steps that will determine what's machined wrong. Except for bleeder valve location, the calipers are interchangeable side to side. See if the passenger side caliper will bolt up on the driver side.. If so, you'll know the caliper is the problem. If it won't fit, the spindle is the problem.. Don't grind any parts, replace the spindle.

[Dashman]

I have an eye of a remanufacturer caliper that is out of round as if someone dropped it. I haven't installed it yet, but I'll have to do something about it. Just saying that the remanufactured calipers aren't perfect.

With your caliper removed, I would try to put a straight edge on the caliper bracket at the holes and compare it to the rotor for parallel. It's the threads in the caliper bracket that determine if the bolt is going across perpendicular to the rotor. You may have to remove it, apply some heat and pressure to bend it straight again. ..or perhaps someone cross threaded it in the past?

[weq92f]

Originally Posted by Dashman

I have an eye of a remanufacturer caliper that is out of round as if someone dropped it. I haven't installed it yet, but I'll have to do something about it. Just saying that the remanufactured calipers aren't perfect.

With your caliper removed, I would try to put a straight edge on the caliper bracket at the holes and compare it to the rotor for parallel. It's the threads in the caliper bracket that determine if the bolt is going across perpendicular to the rotor. You may have to remove it, apply some heat and pressure to bend it straight again. ..or perhaps someone cross threaded it in the past?

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The pin makes contact with the outboard spindle mount hole off center before it mates with the threads in the inboard spindle mount hole.

I can start threading the pin through the outboard mount hole on either the top or bottom mount point, but the remaining pin then will not line up without putting things in a bind (I can get the second one started by applying pry bar pressure but it is way too tight).

I'm not understanding the straight edge parallel to rotor comment.

Thanks,

-Kevin

[72c20customcamper]

You can try the other caliper on the side giving you problems . The mounting should be the same the only thing different between right and left is the bleeder orientation . If it goes on then the caliber is the problem if it’s the same something wrong with it the spindles mount .

[RustyPile]

Originally Posted by 72c20customcamper

You can try the other caliper on the side giving you problems . The mounting should be the same the only thing different between right and left is the bleeder orientation . If it goes on then the caliber is the problem if it’s the same something wrong with it the spindles mount .

I suggested a variation of the same suggestion in post #4. Maybe now he'll follow our advice and solve his problem.

[weq92f]

Originally Posted by RustyPile

I suggested a variation of the same suggestion in post #4. Maybe now he'll follow our advice and solve his problem.

.

Yes you did. Thank you! Had some other things take me away from it so this will get done however, I have verified the issue is most likely user error or the the spindle is not right. I purchased another caliper from a different parts house and found it too doesn’t line up.

I’ve done the rotors and pads brake service on this truck in the past without trouble. The calipers were sticking in this case. Only difference is new calipers and I’m not going back with new pas right now. Maybe I should as that would align the caliper over top of rotor more precisely. Come to think of it this is the first time I’ve attempted reassembly without all new rotors and pads!

I appreciate your help Sir.

-Kevin

[Dashman]

Sorry, I didn't read your post thoroughly. You said, ECE drop spindles, and I was assuming a caliper bracket. Your knuckles have spindles and a forged caliper bracket. I had to check out this post for photos:

https://67-72chevytrucks.com/vboard/...d.php?t=806491

I understand the inside of the bolt holes is a rough surface, but there are two machined surfaces that encompass the caliper that are machined. You could check those for parallel to the rotor. Seems like something changed from the initial installation of those knuckles. I still think some heat and pressure could solve it. Good luck.

[raggedjim]

The replacement calipers are not cast correctly. I ground the caliper in the area shown in the attached post. When the guys who designed the drop spindles designed them they designed them to fit original calipers, not the crap that is coming out of China today.

Good luck, Rg

https://67-72chevytrucks.com/vboard/...0&postcount=81

[weq92f]

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My caliper needed some trimming, like 1/16th, off the bit that comes into contact with the spindle. Fit fine after that. Did some bleeding and found one of the caliper piston dust boots isn't attached to the caliper, only the piston.

Oh and now my brakes don't drag at all...instead, they lock completely up, both sides! Fun.

-klb