Stripped brake caliper thread

Hello,
I have stripped one of the two mounting threads of my 95's front brake caliper. Will a helicoil be 100% safe? This is my main concern.
Thank you

Mikel :doh:

Mikel said:

Hello,
I have stripped one of the two mounting threads of my 95's front brake caliper. Will a helicoil be 100% safe? This is my main concern.
Thank you

Click to expand...

yes it will be. i have been using one for a little while, and i know many others around here have as well

Should have searched. Found all kinds of info, but can't delete the thread.

I would replace it with a new/rebuilt unit and turn in the damaged one as the core. Brakes are TOO important to use a helicoil on. I work as an engineer in Aviation and the old guy in structures was telling me how heli-coils were just a bad idea.

Spend the money and replace the caliper also I'd install it with a hew hose and renew that side of the vehicle. I do not want you to be that one guy who went cheap and ended up hurting someone if the helicoil let go.

I am the type who would replace a part to remove all doubt. When I go cheap I end up paying even more than if i fixed it right the first time.

martin said:

I would replace it with a new/rebuilt unit and turn in the damaged one as the core. Brakes are TOO important to use a helicoil on. I work as an engineer in Aviation and the old guy in structures was telling me how heli-coils were just a bad idea.

Spend the money and replace the caliper also I'd install it with a hew hose and renew that side of the vehicle. I do not want you to be that one guy who went cheap and ended up hurting someone if the helicoil let go.

I am the type who would replace a part to remove all doubt. When I go cheap I end up paying even more than if i fixed it right the first time.

Click to expand...

the knuckle is threaded, not the caliper. he would need a whole new knuckle. if it were only the caliper, I would also suggest replacing it.

I did not like the idea of using a helicoil either (just ask geoff) but did some searching and found others with no issues with them in this application.

martin said:

I would replace it with a new/rebuilt unit and turn in the damaged one as the core. Brakes are TOO important to use a helicoil on. I work as an engineer in Aviation and the old guy in structures was telling me how heli-coils were just a bad idea.

Spend the money and replace the caliper also I'd install it with a hew hose and renew that side of the vehicle. I do not want you to be that one guy who went cheap and ended up hurting someone if the helicoil let go.

I am the type who would replace a part to remove all doubt. When I go cheap I end up paying even more than if i fixed it right the first time.

Click to expand...

I believe that the threads in question are in the spindle, not the caliper.

I've seen lots of stripped bolts on calipers of this design. Your best bet is to get a new bolt. As for the threaded hole, you don't even need a HeliCoil...you can just run a tap through it and renew the threads....unless it's stripped to the point of the hole being too large for the tap.

Aviation brakes don't have much in comon with XJ brakes. On a Cessna for example, the bolts retain the pads and hold the caliper to the strut. The bolts in that instance absorb the forces of stopping the Aircraft. On a Jeep, the knuckle retains the pads, and absorbs the force of the braking action. The bolts are only there to locate and guide the caliper.

The bolts screw into the knuckle or bracket (depending on what version of knuckle you have). Helicoils are a good fix. New bolts and lots-O-antiseize is a good idea also.

I've been running on helicoils for my drivers front knuckle for over 18 months. Never an issue.

While I was posting I was trying to remember if the female thread was in the caliper or was it on the spindle. It been 3 or 4 years since I pulled off a caiper and was having problems recalling.

My recommendation is to change out the piece with the stripped threads - caliper or spindle. Helicoil is an unacceptable repair in my mind. Just because helicoils are out there does not mean they are smart to use, it comes down to how much you value your life of the life of your family members.

I don't know what planet you came from assuming I was talking about avaition brakes. The aircraft I work on have skids and are made my Bell Helicopter, it is just stupid to carry around the ground handling wheels 100 percent of the time, they weight too much. I was talking in terms of a bolt being loaded in shear, basic machine design stuff when I mentioned the structures guy opinion. Good engineering practice is good engineering practice PERIOD. I will just say as a Registered Professional Engineer you would never find my seal on this repair if it involved using a helicoil - replacement of the damaged threaded piece is the only repair I'd sign off on.

i first replaced my drivers side knuckle after stripping it out... then after i stripped it out a second time i just ran and got some helicoils and haven't had any problems since.

martin said:

Good engineering practice is good engineering practice PERIOD. I will just say as a Registered Professional Engineer you would never find my seal on this repair if it involved using a helicoil - replacement of the damaged threaded piece is the only repair I'd sign off on.

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On your vehicle, do what you like. The guy asked for advice and we're giving hime some pearls.

As for my explaination of brake systems, I assumed it would help you. Guess not <shrug>

Well I think that all those great engineers at chrysler could have figured out this stripped thread problem. It happes so much on XJ's. I almost find it sad, yet a bit humorous that a Helicoil fits better and is stronger then the OEM knuckle threads.

helicoils are used in all kinds of applications from racing to factory equipment. they're not really much different from tapping a hole. you still have to tap the tread for the helicoils, then insert the coil and then when you put the bolt in the coils get's tightened in. if you're really worried about it, you can put red loctite in the coil, run a bolt through real quick to distribute the loctite and then pull the bolt back out. give the loctite time to dry and now you have a tightly seated helicoil.

some factory aluminum parts have helicoils built right in to reduce the chances of the aluminum treads getting stripped out.

martin said:

I would replace it with a new/rebuilt unit and turn in the damaged one as the core. Brakes are TOO important to use a helicoil on. I work as an engineer in Aviation and the old guy in structures was telling me how heli-coils were just a bad idea.

Spend the money and replace the caliper also I'd install it with a hew hose and renew that side of the vehicle. I do not want you to be that one guy who went cheap and ended up hurting someone if the helicoil let go.

I am the type who would replace a part to remove all doubt. When I go cheap I end up paying even more than if i fixed it right the first time.

Click to expand...

If I am not mistaken, helicoils are used as OEM on many aircraft recip. engines where the bolts or studs screw into the crankcase halves.

They do this so that when tightening the threads, their is a steel on steel sliding action.

If helicoils are used in that application, thiey are probably good to go on automotive brakes.

I've never seen helicoils on OEM, but I have seen plenty of steeel inserts in soft metals and plastics.

We use aircraft inserts (OEM helicoils) in the stack bolts of our pumps where the steel bolt meets the aluminum end plate. They were invented by the aircraft industry for this purpose and only later used for repairs. When you are bolting to a material that is softer than the bolt the shear plane is at the root of the taped hole. If you use an insert the shear plane moves out to the root of the hole taped for the insert. A larger diameter shear area equals a stronger fastener connection. For our application it allows us to use a #10 bolt rather than a ¼-20 and it is still stronger. Our application is nearly all tention.
That said… I think the bolts in question are the big shoulder bolt things that locate the caliper and it seems to me they are side loaded, so what I just said may not be directly applicable.

I have had to have Heli Coils installed on a couple of my work vehicles(stripped out spindles). These vehicles averaged about 70K miles a year, with a lot of stop and go city driving and I'm glad to say I NEVER had a problem with them stripping or failing.
Let your conscience be your guide, but as for me I would not hesitate to use them again.

Helicoils will work, just make sure you tap the hole straight or else............ bad things happen.