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Why you shouldn't split your calipers(and why I do anyways)

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converse212 Avatar
converse212 Eric Morgan
Tucker, Georgia, USA   USA
1958 MG MGA
1970 MG MGB "Daily Driver"
1970 MG MGB GT "Rusty"
1971 MG MGB GT    & more
I rebuilt a new set of calipers for the B today, as I've been fighting a nasty brake squeal and decided it was time anyhow. When I build calipers, I ALWAYS split the halves, against the recommendations of Moss and the Factory Service Manual, as I don't really see an effective way to clean the caliper as much as I like to clean them without splitting the halves. Well, that's not quite true. Moss says not to split them...the FSM says not to reuse the bolts which hold the caliper halves together.

There's been much discussion over the years about this issue, and by and large people have summarily ignored the FSM, stating the reason for not reusing the bolts is that they are designed to stretch when they reach the proper torque and this is the reason they shouldn't be reused.

In actuality, the reason they should not be reused is that they have a locking device on the threads that holds the bolts in place. The locking section is a slightly discolored circle near the end of the bolt in the photo below. This is similar to never using nylock nuts twice...good practice, but in reality best left up to judgement.

So, in summary, there is a reason the factory said not to reuse bolts, it is not that the bolts stretch, and I reused mine anyways and haven't died due to caliper failure.



Daily driving a '71 MGB

Resurrecting a '58 MGA

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33EJB Avatar
33EJB Tim C
LS, Eastern Ontario, Canada   CAN
1969 MG MGB
That "locking device" looks just like a dab of threadlocker to me.

RAY 67 TOURER Avatar
RAY 67 TOURER Ray Marloff
Fort Bragg, CA, USA   USA
1967 MG MGB "My Girl"
X 2. RAY

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converse212 Avatar
converse212 Eric Morgan
Tucker, Georgia, USA   USA
1958 MG MGA
1970 MG MGB "Daily Driver"
1970 MG MGB GT "Rusty"
1971 MG MGB GT    & more
In reply to # 3626083 by 33EJB That "locking device" looks just like a dab of threadlocker to me.

Have you ever taken apart a bolt that was put in with thread locker? It smears all over the threads as the bolt is screwed in. Show me a dab of thread locker on a bolt that's been in situ for 40 years and then removed with an impact gun and I'll eat my hat.

This is most definitely not thread locker. It's a bolt like THESE, similar concept to nylock nuts but applied on the male threads.



Daily driving a '71 MGB

Resurrecting a '58 MGA

33EJB Avatar
33EJB Tim C
LS, Eastern Ontario, Canada   CAN
1969 MG MGB
In reply to # 3626098 by converse212
In reply to # 3626083 by 33EJB That "locking device" looks just like a dab of threadlocker to me.

Have you ever taken apart a bolt that was put in with thread locker? It smears all over the threads as the bolt is screwed in. Show me a dab of thread locker on a bolt that's been in situ for 40 years and then removed with an impact gun and I'll eat my hat.

Have you ever seen a bolt that has had a dab of threadlocker applied before it's been screwed in with an impact gun and in situ for 40 years?

That's what I'm talking about. No hat-eating required.

Diver648 Gold Member Warren Siringer
Tucson, Arizona, USA   USA
1967 MG MGB
1967 MG MGB GT
1971 MG MGB GT
1974 MG MGB
This is 50 year old technology. Newer vehicle caliper bolts use what looks like blue threadlocker from the manufacturer. If it is good enough for my Mustang Gt, it is probably acceptable for my MGB. All the calipers I have split have needed new O rings from deterioration. I always use new caliper bolts when available.

converse212 Avatar
converse212 Eric Morgan
Tucker, Georgia, USA   USA
1958 MG MGA
1970 MG MGB "Daily Driver"
1970 MG MGB GT "Rusty"
1971 MG MGB GT    & more
In reply to # 3626106 by 33EJB
In reply to # 3626098 by converse212
In reply to # 3626083 by 33EJB That "locking device" looks just like a dab of threadlocker to me.

Have you ever taken apart a bolt that was put in with thread locker? It smears all over the threads as the bolt is screwed in. Show me a dab of thread locker on a bolt that's been in situ for 40 years and then removed with an impact gun and I'll eat my hat.

Have you ever seen a bolt that has had a dab of threadlocker applied before it's been screwed in with an impact gun and in situ for 40 years?

That's what I'm talking about. No hat-eating required.

Ah, I understand. Those bolts are exactly as they were removed from the caliper, I had done nothing to them besides clean the threads. No threadlocker applied at any point in the process



Daily driving a '71 MGB

Resurrecting a '58 MGA

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Boris67MGB Richard Boris
Kings Park. NY 11754, USA   USA
1967 MG MGB
Not sure where the notion that Lockheed didn't want the calipers split? Since they use to sell a caliper overhaul kit with new bolts and the internal fluid seal. You can find these NOS Lockheed kits periodically on e-bay.

Boris67MGB Richard Boris
Kings Park. NY 11754, USA   USA
1967 MG MGB

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MGB567 Avatar
MGB567 Gold Member Barrie Braxton
Sunshine Coast, Queensland, Australia   AUS
1966 MG MGB MkI "Money Guzzler"
1979 MG MGB GT V8 Conversion "Darkside"
"Not sure where the notion that Lockheed didn't want the calipers split?"

Maybe this which debunks the notion.



Convertible: CKD 11/66 first registered 8/5/67. Owned since 3/77. 90% original sheet metal. 18GB +40 balanced with almost all new internals. Peter Burgess big valve fast road head. Piper 285. Fidanza FW. Basil's followers and pushrods. TR7clutch. TT exhaust. ARP everywhere. 123 ign. Needham 4synchro c/r box.. Stock rebuilt/replaced suspension. Superpro bushes. New brakes all round including all pipes in SS flex. Interior redone. CAMS approved roll bar and side bars. Lots more. Hybrid of o/e and show/fast road car. Not for sale - it's my toy!

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Basil Adams Avatar
About 12 miles from Sears Point, CA, USA   USA
I was always told not to split the halves because there were no o-rings for that fluid passage. I found some NOS ones in a buyout about 15 years ago and "loaned" a few to a supplier. They had them remade to exacting standards and thanked me with a bag of 100 of them smiling smiley Since then, everyone can get them and the reason not to split has vaporized. As for bolts, I always use new ones and a dab of blue loctite and have never had an issue. Nowadays, new calipers are so inexpensive that it's hardly worth rebuilding! Basil 707.762.0974 basiladams@yahoo.com



Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
1972 Alfa Romeo Montreal
A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

ddubois Avatar
ddubois Gold Member Dave DuBois
Bremerton, WA, USA   USA
Quote: As for bolts, I always use new ones

There in lies the reason not to split the calipers - If the correct bolts are used in rebuilding the calipers, just like using new head bolts whenever the engine head is reinstalled. Yes, the used bolts may not have been over stretched, but I would certainly bet my life on it.
Cheers,



Dave DuBois
1953 MGTD
1966 MGB
http://homepages.donobi.net/sufuelpumps/


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OzDave Avatar
OzDave Dave Barton
London, Ontario, Canada   CAN
In reply to # 3626170 by MGB567
Maybe this which debunks the notion.

Nice article Barrie. It says "torque to a reasonable spec". I'd be interested to hear a few thoughts on what that number should be as I've yet to come across that spec anywhere I've looked.

barry s Avatar
barry s Silver Member Barry Stoll
Alexandria, VA, USA   USA
1972 MG MGB GT
1974 MG MGB
1976 Triumph TR6
1980 MG MGB
Bentley states torque of 35.5 - 37 lb.ft. (Section M6)

the omega man Avatar
the omega man phil wilkins
staffordshire, Stafford, UK   GBR
Fit new calipers and forget about it.

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