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Brake Caliper Banjo Fitting by KensCircus
Started on: 10-25-2013 09:00 AM
Replies: 12 (708 views)
Last post by: KensCircus on 10-26-2013 05:30 PM
KensCircus
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Report this Post10-25-2013 09:00 AM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post
My 87 Fiero GT has 88 Camaro rear brake calipers with braided steel hoses. That information is probably not relevant, but I threw it in anyway.
My question stems from replacing the brake calipers. After replacement, I noticed a leak at the banjo fitting on the caliper casting side. I had hand tightened the fitting and wasn’t sure if I torqued it enough or too much. I found the torque specification to be 22 ft-lbs. for the Camaro calipers. As I began tightening I found the torque stopped increasing at 13 ft-lbs. while the bolt was still turning. I found this alarming, assuming the bolt or casting was stripping out, so I stopped at a little less than a ¼ turn past the point where the torque stopped increasing. The other thought is perhaps that is the normal action of compressing the copper washers? So, what do you think? Is this normal – due to washer compression? Should I keep torqueing? Should I remove the fitting and inspect the threads?
Buy the way, the leak stopped and the 13 ft-lb plateau occurs the same on both calipers.

Thanks for your thoughts,

Ken

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jaskispyder
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Report this Post10-25-2013 09:24 AM Click Here to See the Profile for jaskispyderSend a Private Message to jaskispyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
aluminum caliper?
I tighten the bolts just enough so they don't leak... otherwise it is easy to strip out the bolt hole (aluminum) even with a torque wrench (ones I can afford).
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KensCircus
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Report this Post10-25-2013 09:37 AM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cast Iron.
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jaskispyder
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Report this Post10-25-2013 09:45 AM Click Here to See the Profile for jaskispyderSend a Private Message to jaskispyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would assume it was the copper washer then (new washer?).
Keep an eye on it and if it doesn't leak, I would call it good. your torque wrench could be off, just an example.
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KensCircus
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Report this Post10-25-2013 09:59 AM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was suspicious of the torque wrench so I tried another one (different type) and got the same result.
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KensCircus
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Report this Post10-25-2013 10:01 AM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post

KensCircus

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Yes, new washers. Came with the calipers.
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jaskispyder
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Report this Post10-25-2013 10:07 AM Click Here to See the Profile for jaskispyderSend a Private Message to jaskispyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
I torqued down an '88 fiero caliper banjo bolt once.... and had to replace the caliper after it stripped out

I usually tighten them by hand so as they don't leak. At least with cast, you probably didn't ruin anything and the washer is just crushed, properly.
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theogre
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Report this Post10-25-2013 10:10 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
"As I began tightening I found the torque stopped increasing at 13 ft-lbs. while the bolt was still turning." Ouch.
"Is this normal" No.
"Should I remove the fitting and inspect the threads?" Yes. More like, Get another caliper.

If SS lines use round Universal ends, they can work loose from driving, service, etc..
Some SS lines use same caliper ends as rubber hoses. That type is nearly impossible to come loose.
see http://www.fiero.nl/forum/F...HTML/129208.html#p38

Read the rest of thread too...

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KensCircus
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Report this Post10-25-2013 12:28 PM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks Orge and Jaskispyder,

My confusion is that the published specification for the banjo bolt is 22 ft-lbs, while 13 seems to be too much?

I have had the car since 2003. It is my daily driver. Has had this brake setup from the start; same calipers, steel hose and all. Never a speck of issue with it. Excellent braking performance. I like to keep things new - thus the caliper replacement. This is the first time I have ever put a torque wrench on a banjo bolt, but I use torque wrenches a lot - on every thing else that is critical. I have never run into an issue where published torque specs resulted in stripped threads. First time for everything, I guess.
Oh well, looks like another set of calipers!

In any event, what do you make of the torque spec thing??? Buy the way, the washers do fit the banjo bolt and fittings.

Thanks,

Ken
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theogre
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Report this Post10-25-2013 08:29 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cast Iron caliper should take allot more torque then 13ftlb...
the hole and/or bolts is stripped. very likely
bolts is wrong size. unlikely

Do Not drive the car. It may hold for now then nothing at a stoplight etc.

Front brakes does 75-90% of stopping depending on speed etc.
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KensCircus
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Report this Post10-26-2013 07:14 AM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post
No worries. I would never drive with questionable brakes.

The "new" calipers are re-manufactured, but from different rebuild houses - assumption due to different box printing.
The bolts are original - not new.
The "new" calipers appear and fit identical to the original. All have the same casting number.
There was nothing remarkable about un-bolting it in the fist place. They did not seem "unusually" tight or loose.

I haven't had a chance to take them back off for inspection, but I suspect I will be getting another set of "new" calipers and bolts.
Then, I will be very concened about attempting to torque it to the 22 ft-lb spec. Any suggestions there?

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hobbywrench
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Report this Post10-26-2013 02:09 PM Click Here to See the Profile for hobbywrenchSend a Private Message to hobbywrenchEdit/Delete MessageReply w/QuoteDirect Link to This Post
The cast iron has probably been over torqued and pulled the female threads. I could see this done by attempting to reuse the copper washers. The hopeful mechanic thinks he can chase down a good seal with just a little more torque. NO NO. Once crushed washers harden and require replacement. In the old days stores charged outrageous prices for copper washers. I have used the H-Frt fishing- tackle- box- selection with success several times. In a pinch I have annealed used washers with a gas torch, but new is the way to go.

Jump to the aluminum calipers...I received a rebuild from Auto Zone where the E brake clip holes would not torque. My take was that the caliper had been overheated. It only takes 350F+ to change the alloy structure. I have measured the disc temps during normal driving at 250F. If the E brake causes drag the temp can quickly rise. The core processors most likely do not do a hardness check before rebuild. No solution to this crap shoot during replacement, I guess.

[This message has been edited by hobbywrench (edited 10-27-2013).]

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KensCircus
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Report this Post10-26-2013 05:30 PM Click Here to See the Profile for KensCircusClick Here to Email KensCircusSend a Private Message to KensCircusEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by hobbywrench:

The cast iron has probably been over torqued and pulled the female threads. I could see this done by attempting to reuse the copper washers. The hopeful mechanic thinks he can chase down a good seal with just a little more torque. NO NO. Once crushed washers harden and require replacement. In the old days stores charged outrageous prices for copper o rings. I have used the H-Frt fishing- tackle- box- selection with success several times. In a pinch I have annealed used o rings with a gas torch, but new is the way to go.

Jump to the aluminum calipers...I received a rebuild from Auto Zone where the E brake clip holes would not torque. My take was that the caliper had been overheated. It only takes 350F+ to change the alloy structure. I have measured the disc temps during normal driving at 250F. If the E brake causes drag the temp can quickly rise. The core processors most likely do not do a hardness check before rebuild. No solution to this crap shoot during replacement, I guess.


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