Caliper thumping problem became obvious.

[Zymurgy]

2 weeks ago I was coming home and was about a mile from home and when I hit the brakes this horrible thumping occurred on the right front brakes. Stop looked, didn't notice an obvious problem, but was leaking brake fluid and limped home.

As many of you know I had an epic disc brake conversion, so I thought what now. I took the wheel off and fluid was leaking where the rubber hose entered the caliper. Decided the few times I overheated the brakes I might have damaged the hose or caliper. Ordered both since they are pretty cheap.

Today I went to work on Goldie, first the hose was loose so the thumping must have loosen it and then the real problem was revealed. The lower mount bolt was gone.

After 2 trips to the hardware store I am back on the road. No damage seems to have occurred.

If anyone has a a spare mounting bolt laying around I would be interested in purchasing it. It is 1/2" 20, 2" long. Wrench head is a 3/4.

 

[commando1]

In my 5 gal pail, all I could come up with was course thread.

 

[Zymurgy]

In my 5 gal pail, all I could come up with was course thread.

Thanks for looking for me Stan

 

[Ross Wooldridge]

Interesting. Wondering if thread locker should be applied when I reassemble after servicing.

 

[Zymurgy]

Interesting. Wondering if thread locker should be applied when I reassemble after servicing.

We are on the same page, I put some thread lock when I reassembled. I know I torqued it to spec the first time, not taking any chances this time. The heat from overheating the brakes maybe loosened thing up. I never rechecked the torque afterwards.

 

[CBODY67]

Hope your "hardware store bolt" is of the same hardness rating as the OEM part!

Did you replace the copper seal washers between the hose connections and the calipers??????

CBODY67

 

[mopar_4life]

Take it to fastenal and have them find the correct bolt. Also if you know the size, ARP Bolts.

 

[Zymurgy]

Hope your "hardware store bolt" is of the same hardness rating as the OEM part!

Did you replace the copper seal washers between the hose connections and the calipers??????

CBODY67

Yes and yes

 

[LocuMob]

We are on the same page, I put some thread lock when I reassembled. I know I torqued it to spec the first time, not taking any chances this time. The heat from overheating the brakes maybe loosened thing up. I never rechecked the torque afterwards.

I know I've beaten on newer cars and had some hot brakes, but never had anything loosen up on me. I'd talk to your mechanic and make sure he torques it correctly! Just glad you and Goldie didn't get hurt.

 

[Zymurgy]

Take it to fastenal and have them find the correct bolt. Also if you know the size, ARP Bolts.

I have a Fastenal store in my town, I was going to go there first, but it closed at noon.
I have have a bolt that will work for now it is a 1/2" shorter but with the thinner washer and the unthreaded end I will work fine for now. Just want the Mopar bolt more than anything, for me.

 

[Zymurgy]

I know I've beaten on newer cars and had some hot brakes, but never had anything loosen up on me. I'd talk to your mechanic and make sure he torques it correctly! Just glad you and Goldie didn't get hurt.

Thanks, who knows I had it apart so many times, I know I torqued it the first time. This is coming from the guy who drove around the block with lugnuts only finger tight, so anything is possible.

 

[Davea Lux]

2 weeks ago I was coming home and was about a mile from home and when I hit the brakes this horrible thumping occurred on the right front brakes. Stop looked, didn't notice an obvious problem, but was leaking brake fluid and limped home.

As many of you know I had an epic disc brake conversion, so I thought what now. I took the wheel off and fluid was leaking where the rubber hose entered the caliper. Decided the few times I overheated the brakes I might have damaged the hose or caliper. Ordered both since they are pretty cheap.

Today I went to work on Goldie, first the hose was loose so the thumping must have loosen it and then the real problem was revealed. The lower mount bolt was gone.

After 2 trips to the hardware store I am back on the road. No damage seems to have occurred.

If anyone has a a spare mounting bolt laying around I would be interested in purchasing it. It is 1/2" 20, 2" long. Wrench head is a 3/4.

View attachment 146338

I have several OEM if you can't find them. They have some minor rust from laying around for 30 years but they will clean up nice. You can PM me with contact info if you are interested. Free is a very good price.

Dave

 

[Zymurgy]

I have several OEM if you can't find them. They have some minor rust from laying around for 30 years but they will clean up nice. You can PM me with contact info if you are interested. Free is a very good price.

Dave

Thanks Dave you're the man. I have a local friend who is going to look in his stash. If he doesn't find one I will send you a PM, thanks for your help.

 

[LocuMob]

Thanks, who knows I had it apart so many times, I know I torqued it the first time. This is coming from the guy who drove around the block with lugnuts only finger tight, so anything is possible.

I recheck everything 3-4 times out of paranoia, "did I check that?" Everything except the lug nuts on my truck, I have done that twice, never again!

 

[Davea Lux]

Thanks, who knows I had it apart so many times, I know I torqued it the first time. This is coming from the guy who drove around the block with lugnuts only finger tight, so anything is possible.

Note that these bolts should always be installed with locktite.

Dave

 

[Wonderwagon]

OEM was grade 5, I believe.

 

[Zymurgy]

OEM was grade 5, I believe.

I installed a grade 8 so I should be good.

 

[Davea Lux]

I installed a grade 8 so I should be good.

Grade 8 bolts are significantly harder than grade five bolts, that also makes the grade eight bolts more brittle. Suggest you go with the grade five as they will stand up better under conditions of flexing and be less likely to cold work and break.

Dave

 

[Zymurgy]

Grade 8 bolts are significantly harder than grade five bolts, that also makes the grade eight bolts more brittle. Suggest you go with the grade five as they will stand up better under conditions of flexing and be less likely to cold work and break.

Dave

Good information thanks

 

[CBODY67]

How many marks on the top of the other bolts?

The time I went to the local Fastenal, to look for a bolt for a guy at work, they said they only sold "in quantity", not singles. They might have a good selection, but only "in unit pack quantities", it seems.

CBODY67