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2004 BMW 330ci M-sport
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Discussion Starter · #1 ·
This past week I was upgrading my brake pads and after putting everything back together, I went out for a drive and a few miles in I started to hear this terrible rattling that turns out to be due to my caliper guide pins backing themselves out a few threads. I've replaced the pins themselves as well as the anti rattle clip (which strangely made a difference for a few days). They keep coming out. It just takes a few minutes on a backroad after tightening. My only thought would be that I stripped the receiving threads on the caliper carrier but the threading looks the same as all the other non rattling ones. Anyone have any thoughts?
 

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This past week I was upgrading my brake pads and after putting everything back together, I went out for a drive and a few miles in I started to hear this terrible rattling that turns out to be due to my caliper guide pins backing themselves out a few threads. I've replaced the pins themselves as well as the anti rattle clip (which strangely made a difference for a few days). They keep coming out. It just takes a few minutes on a backroad after tightening. My only thought would be that I stripped the receiving threads on the caliper carrier but the threading looks the same as all the other non rattling ones. Anyone have any thoughts?
Are you torquing them up properly? Did you get grease on the threads? You are supposed to grease them but not on the threads. Clean the threads on the pins and the carrier with brake cleaner and use a torque wrench to tighten them up to 35 Nm / 25 ft lbs
 

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2004 330CI ZHP
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308 Posts
Strange, I have the opposite experience. The threads for the slide pins in my front caliper carriers were all stripped, yet everything would function as it should and they would never back out. Sounds like a very odd situation that you have - I was thinking maybe there is some weird vibration that could cause that, but the slide pin bushings should dampen all of that out
 

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2004 330Ci 115k miles
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16,723 Posts
I usually don’t grease them, just keep them clean and inspect for corrosion.
I have hit the guide pin surfaces with a light coat of silicone spray a few times before installing.
 

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Definitely don't wanna use anything on the guide pins except silicone (if anything at all).

I found this out the hard way. I used caliper grease on the pins when I first bought my e46 and it turned into a black sticky tar within months!!

This is the silicone I use. I just can't accept keeping them dry. But BMW says so.

If you need some new guides and pins I have tons! When I ruined my first set I went the junkyard and grabbed a boatload. PM me and they're yours free, just pay for shipping.


Sent from my ONEPLUS A6000 using Tapatalk
 

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Strange, I have the opposite experience. The threads for the slide pins in my front caliper carriers were all stripped, yet everything would function as it should and they would never back out. Sounds like a very odd situation that you have - I was thinking maybe there is some weird vibration that could cause that, but the slide pin bushings should dampen all of that out
Why you didn't you replace the stripped pins? What if they fell out and you loose brake?
The caliper doesn't put load on the pin normally and this is why yours still working. But if the dust cap fell off then the pin will follow out too then disaster
 

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This past week I was upgrading my brake pads and after putting everything back together, I went out for a drive and a few miles in I started to hear this terrible rattling that turns out to be due to my caliper guide pins backing themselves out a few threads. I've replaced the pins themselves as well as the anti rattle clip (which strangely made a difference for a few days). They keep coming out. It just takes a few minutes on a backroad after tightening. My only thought would be that I stripped the receiving threads on the caliper carrier but the threading looks the same as all the other non rattling ones. Anyone have any thoughts?
I believe the calipers were installed incorrect, leading to caliper pushed a big load on the guide pin during braking. For front brake, the caliper wants to rotate up during braking but it is stopped by the carrier at the top rail. Look careful and make sure the caliper 4-point contacts are locked within the carrier rails, at top and at bottom. IF it was installed correctly, during braking the guide pin should have no load pushed on by the caliper.
 

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2004 330CI ZHP
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Why you didn't you replace the stripped pins? What if they fell out and you loose brake?
The caliper doesn't put load on the pin normally and this is why yours still working. But if the dust cap fell off then the pin will follow out too then disaster
Lol chill. I have a good set of caliper carriers sitting in my garage, to be installed once my car comes out from winter storage
 

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Female. Or else I wouldn't have gotten the carriers
Got it. They are steel and someone heavy handed the bolts with extra torque thinking safety. I recently bought my new 2003 325iT and the 13mm bolt holding the steering pump rear bracket to the OFH bottom female threads were stripped. Hate people don't have calibrated arms. Just bought another used OFH and swap them out, but I might use helicoil insert to fix it.
 

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2004 330CI ZHP
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Got it. They are steel and someone heavy handed the bolts with extra torque thinking safety. I recently bought my new 2003 325iT and the 13mm bolt holding the steering pump rear bracket to the OFH bottom female threads were stripped. Hate people don't have calibrated arms. Just bought another used OFH and swap them out, but I might use helicoil insert to fix it.
It's horrible, and I think I know who did it - right when I bought the car it needed new pads & rotors to pass safety inspection, so the PO brought it to some random shop which threw shit no-name brand parts on the car. At the time I did at most autox so I never needed to swap the brakes out. And only last year I started going to the track, so I replaced the brakes for the first time... turns out I had been driving on stripped guide pins for 5 years :eek:. I installed helicoils in the carriers but they would occasionally back out when swapping pads, and they'd tighten, but not to torque specs. M9 helicoils are hard to come by so I found a set of good used carriers locally.

Another reason why I know it was that shop that did the safety cert: The caliper to upright mounting bolts were torqued to infinity. I did not have an impact wrench at the time, and even pulling with all my might on the breaker bar, I couldn't break it loose. I ended up having to improvise and finally got those bolts loose by using my floor jack to push up on the end of the breaker bar.

... and this (and a couple other stories) is why I do all my own work on my car.
 

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Another reason why I know it was that shop that did the safety cert: The caliper to upright mounting bolts were torqued to infinity. I did not have an impact wrench at the time, and even pulling with all my might on the breaker bar, I couldn't break it loose. I ended up having to improvise and finally got those bolts loose by using my floor jack to push up on the end of the breaker bar.
You meant the caliper carrier mounting bolts -- the big ones like 16 or 17mm. I bet those guys used impact wrench on all these bolts, including the caliper smaller guide pins and stripped them easily.
When I bought my E46 M3 and wanted to remove the wheels to check the brake pads condition, I couldn't loosen the wheel bolts and broke a 19mm (or 17mm) socket using a long breaker bar. Finally I got an impact socket and got them off. They were torqued to more than double the spec I think.
 

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2004 BMW 330ci M-sport
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Discussion Starter · #14 ·
Definitely don't wanna use anything on the guide pins except silicone (if anything at all).

I found this out the hard way. I used caliper grease on the pins when I first bought my e46 and it turned into a black sticky tar within months!!

This is the silicone I use. I just can't accept keeping them dry. But BMW says so.

If you need some new guides and pins I have tons! When I ruined my first set I went the junkyard and grabbed a boatload. PM me and they're yours free, just pay for shipping.


Sent from my ONEPLUS A6000 using Tapatalk
Thanks for all of the ideas. I’ve replaced pins/bolts, but thank you for the offer!!! I didn’t realize that there was a specific torque spec, I had been doing them just hand tight, so we’ll see how they hold up when I go out for a drive tomorrow.
 

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2004 BMW 330ci M-sport
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Discussion Starter · #15 ·
Are you torquing them up properly? Did you get grease on the threads? You are supposed to grease them but not on the threads. Clean the threads on the pins and the carrier with brake cleaner and use a torque wrench to tighten them up to 35 Nm / 25 ft lbs
Ahhh, I hope that’s it. I’d been doing them hand tight, I’ll report back to see if 25ft lbs is enough tomorrow. Thank you
 

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When I bought my E46 M3 and wanted to remove the wheels to check the brake pads condition, I couldn't loosen the wheel bolts and broke a 19mm (or 17mm) socket using a long breaker bar. Finally I got an impact socket and got them off. They were torqued to more than double the spec I think.
I did control arms and an axle for someone and the shop that did the wheel bearings before I got it had the lug bolts so tight my impact wouldn't remove them. I needed a breaker bar with a 4 ft cheater to get them loose. The torque on an xi front axle nut is 300+ ft lbs and the impact spun that one right off.
 

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They're a 'special fastener' not an 8.8. I too tighten them 'hand tight' but I guess I'm more heavy- handed

as I've seen what happens when the lower one comes loose on an E30 with 15" wheels going into
t2 at Spokanistan raceway...

t
 

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2004 325i automagic
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Isn't 35 Nm way too much for their thread (it is M8 I suppose), is it?
The Bentley lists 30Nm or 22 ft-lbs for the guide pins, so it's not too far off. They don't need much.
 

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When the slide pins back, its almost always due to a buildup of grease at the bottom of the hole. When too much grease is applied, it leaves little room for the pin at the bottom and it gets pushed back by the excess grease. Clean the pin and the hole out thoroughly and apply a light coat to the pin only. Should solve your problem.
 
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