1985 300D - Caliper Troubles

[Ya Mar]

Hello All!

I was removing my calipers today and one of the caliper bolts came out in 2 pieces! It had snapped off. This was very sad.

I drilled out the broken off bolt but have now lost all the threads. I was hoping to drive in a bolt and let it make it's own thread but the metal seems too hard.

Does anyone have any ideas?

Is it at all safe to drive with just 1 caliper bolt?

Also, I need to bleed the front brakes but I can't figure out how I'm supposed to do that. Does anyone know?

Thanks!!

[jt20]

Originally Posted by Ya Mar

Is it at all safe to drive with just 1 caliper bolt?

Absolutely not.

The only system a car really needs is brakes.

[jt20]

you need a new spindle / knuckle

or

a machine shop can tap you a new hole and give you the correct bolt for that thread.


or

you can use a heli coil... but that is at your own risk and undesirable to say the least.

[Ya Mar]

I'm thinking about putting a bolt through and using a nut and a washer on the other end, until I can take it to a garage for them to fix it.

I'm not sure if there is enough clearance for me to fit in a nut and a washer, but I'm going to take a look tomorrow morning and see what I think.

[whunter]

Originally Posted by Ya Mar

Is it at all safe to drive with just 1 caliper bolt?

NO...

It is not safe...









.

[whunter]

Originally Posted by Ya Mar

Also, I need to bleed the front brakes but I can't figure out how I'm supposed to do that. Does anyone know?

Automotive repair training book on line, you can download it.
http://www.tpub.com/content/construction/14273/

Brake:
Brake:

[whunter]

Originally Posted by Ya Mar

I'm thinking about putting a bolt through and using a nut and a washer on the other end, until I can take it to a garage for them to fix it.

I'm not sure if there is enough clearance for me to fit in a nut and a washer, but I'm going to take a look tomorrow morning and see what I think.

NO..

That is a critical safety issue.

Get a good used spindle / knuckle..

[layback40]

Ya Mar,
You need to take a trip to a junk yard & get a good second hand one.

Dont try & drive with patched up brakes.

It sounds like you have had "the brake job from hell". Its not normally that difficult.

Best not to try & take a short cut at this stage. See the job through.

Good Luck !!

[Stretch]

Originally Posted by layback40

Ya Mar,
You need to take a trip to a junk yard & get a good second hand one.

Dont try & drive with patched up brakes.

It sounds like you have had "the brake job from hell". Its not normally that difficult.

Best not to try & take a short cut at this stage. See the job through.

Good Luck !!

X2

[t walgamuth]

If a bolt of the same diameter and length can be found of the same strength I don't see why through bolting it, if there is room, won't work. I would take the bolt you are planning to use though to a machine shop and ask them about it's strength.

You can also ask about installing a heli coil on such a part. As you have found the hub carrier is pretty tough material.

(Sorry, but you sound somewhat inexperienced).

Good luck.

[Stretch]

If you want to work out bolt strengths take a look at this link

http://euler9.tripod.com/bolt-database/22.html

Scroll down to the bottom of the page and look at table 10

I think the bolt you'll need will be a 8.8 (stamped on the surface of the hex head)

[vstech]

the problem with a bolt and washer is movement. calipers get a LOT of stress. and unless the bolt is threaded into the knuckle, it'll wiggle on each stop.
don't try to patch this. go get a replacement knuckle and be done with it! as a bonus, the junkyard will still have the bolts for your caliper in it! (be sure to clean the threads and install new BLUE locktite on the threads. or get new bolts from the dealer with thread locker already installed.

[t walgamuth]

As a person with structural training, I believe I am qualified to say that either system will wiggle some. It is the tension which gives the most strength and then the shear capacity of the bolt.

I will modify my recommendation though. I would only do the bolt as a temporary measure until i could change the hub carrier.

[Diesel911]

Originally Posted by vstech

the problem with a bolt and washer is movement. calipers get a LOT of stress. and unless the bolt is threaded into the knuckle, it'll wiggle on each stop.
don't try to patch this. go get a replacement knuckle and be done with it! as a bonus, the junkyard will still have the bolts for your caliper in it! (be sure to clean the threads and install new BLUE locktite on the threads. or get new bolts from the dealer with thread locker already installed.

I agree with the above. With the Original Bolts the unthreaded part of the Bolt allows for alignment in the hole on the Caliper.
If a through bolt and washer move around they will not stay tight.

Another issue is the If you use a Washer it needs to be a hardend one also and as an example a Grade 8 washer is thicker thatn the regular ones; and where would you find Metric one.

Clearly the Original poster does not want to take the Car someplace to have it fixed.
A Heilcoil would work but the PO buggered the hole drilling out the Bolt. I would not expect good luck with him/her drilling a hole for a Heilcoil.

[Ya Mar]

I have a new spindle ordered, it should be here Thursday.