Hi all
I am refurbishing my chevy, now i got another problem , the caliper guide pin was fixed by someone with two washer and a part of M3 screw extending the pin weldin on it and drilled one hole.
done because the thread on mounting bracket is damaged. is very hard to find on scrapyard and now my country is stopped by Covid-19 .
Someone had this problem and how was it solved ?
taking measurement on pin guide the threat would be about 7/16-20 . is it correct ?

thanks from Spain

 

Can you post a picture?

 

 

 

mounting bracket
the upper thread is damaged . i think about several fixing .
1-refill the hole using a 2 part compound like Nural 27 and then make a new thread .
2- refill welding and make a new thread , this option is more complicated , the metal will be hard by temperature and difficult to do.
3- drill a bigger hole and insert and weld piece of metal treaded hole .
4- to do a bigger thread and reduce the diameter with a threaded helicoil but I have metric helicoil . didn't find inch on webs

 

Check out RockAuto, they have them in stock from about $2 -$14 for a pair. From the looks of yours, I'd change out both sides as I can't see how anything can glide on them.

 

hi AJBert
the caliper guide pin are insterted on mounting bracket or Knuckle 14070359, the pins provide the fixing of the calipers but permit them to move lateraly because are a floating calipers . this pin is removed at the time you change the brake pads . so the problem is on knuckle with the thread made on it.
I cheked Rockauto but they dont have this part and it is heavy for transport.

thanks

 

Helicoil to fix the broken thread.

Your own risk! Not too sure if this fix would be an allowable solution to a brake part.

 

hi guys
after thinking a lot , I bought a 7/16-20 helicoil kit for a new thread on knucklw from UK . I hope will be fine , the knuckle is made with molten iron , I have welder for molten MMA electrode but it is complicated to make thread after it because it became hard cooling after hot ,until now the caliper was supported by lower pin screwed only and the upper screw had gap and was fixed with a homemade hair pin at end .
on the left front brake the caliper guide metal boot was missing !!! and the CV boot was not original and it is too big rubbing the shock absorber , the boot is broken but the rubber looks like new.

​​​someone tryed to replace the CV boot from behind ? without removing suspension ?

​​​​I pushed an order to RockAuto for several parts , now only waiting for them doing other task , removing mud and remove oxide ... is more expensive the transport than the parts and I hope the custom look away !!!

 

You could try a broken thread type repair like Heli-Coil as error suggested, but for a critical services like brake parts I would recommend a sleeve type insert like Time-Sert. They are expensive, but proven to work better than the original threads in cast iron. We used them all the time in machine tool fixturing when a hole would wear out from repeated use or misuse from a new guy with a heavy hand.

7/16-20 UNF thread repair options on Amazon


From what I could find on a few websites, the thread size is 7/16-20 UNF for your application, but you would want to verify that before purchasing the wrong kit regardless of which way you go. If you decide to go with the Time-Sert, you'll need to verify the thickness of your part as well and get the insert length that will stay inside the part (i.e. not protrude out the other side). Time-Sert inserts lock in place by deforming the bottom of the insert inside the newly threaded hole. If that portion of the insert protrudes out the back of the part, it could allow the insert to loosen at some point during service.

*EDIT* - Posted at the same time. Heli-Coil should work, just make sure you inspect it every time you remove the pins. Take a picture of the insert after you install it and then clean things up and take another picture down the road to compare to the original to see if anything has moved on you.