Cooper S Brake Calipers Rebuild Problems
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- 850 Super
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Cooper S Brake Calipers Rebuild Problems
Purchased Caparo AP Braking GRK5006 kits for my caliper rebuilds and on the box stated made in the UK.
However, the quality is NOT good.
The wiper seals and the wiper seal metal retainers are too large in diameter to fit the machined recess in the calipers.
Also, the wiper seals are too large in diameter to fit inside the metal retainers.
The metal retainers measure 2.012" O.D. and the machined recess in the caliper measures 1.995" in diameter.
I have crushed or distorted 2 retainers attempting to install.
Now, I must purchase 2 additional kits in hope that those components will have been made to the correct specifications.
Any one else had these issues?
Are the after market caliper kits any better?
Thanks for your help and insight.
Jim
However, the quality is NOT good.
The wiper seals and the wiper seal metal retainers are too large in diameter to fit the machined recess in the calipers.
Also, the wiper seals are too large in diameter to fit inside the metal retainers.
The metal retainers measure 2.012" O.D. and the machined recess in the caliper measures 1.995" in diameter.
I have crushed or distorted 2 retainers attempting to install.
Now, I must purchase 2 additional kits in hope that those components will have been made to the correct specifications.
Any one else had these issues?
Are the after market caliper kits any better?
Thanks for your help and insight.
Jim
- Andrew1967
- 1275 Cooper S
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Re: Cooper S Brake Calipers Rebuild Problems
I had exactly the same problem . Messaged MGBhive where I got them from (via their eBay website) and was told ‘never had any complaints before, we will check and get back to you (never did) …’ and basically F**k off !!
Ended up buying a NOS Lockheed kit and the parts fitted perfectly.
Ended up buying a NOS Lockheed kit and the parts fitted perfectly.
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- 1275 Cooper S
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Re: Cooper S Brake Calipers Rebuild Problems
Had the same problem a few years back. Since then i always order one rebuild Kit in surplus.
I found that it's better to push the retaining ring in wit your thumbs before pressing it in with the tool
I found that it's better to push the retaining ring in wit your thumbs before pressing it in with the tool
I promise i won't buy another MkI...
- Andrew1967
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Re: Cooper S Brake Calipers Rebuild Problems
If Jim had the same problems as me, it’s impossible to get the metal rings in without damage. They are simply far too large.
Genuine Lockheed ones are perfect
Genuine Lockheed ones are perfect
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- 850 Super
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Re: Cooper S Brake Calipers Rebuild Problems
Thank you for your replies.
Do you know the Lockheed brake kit part number?? Possibly find on Ebay or anyone have Lockheed brake kits for sale ??
The wiper seals do not contact the pistons--leaving a gap for water and dirt.
Jim
Do you know the Lockheed brake kit part number?? Possibly find on Ebay or anyone have Lockheed brake kits for sale ??
The wiper seals do not contact the pistons--leaving a gap for water and dirt.
Jim
- Andrew1967
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- 850 Super
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Re: Cooper S Brake Calipers Rebuild Problems
Thanks for your replies.
Andrew, thank you for the Lockheed part number, SSB 2604.
I found 2 kits on Ebay here in the USA and have purchased those. They should be here by Saturday.
This forum is a great place to find the information to keep our Minis alive.
Jim
Andrew, thank you for the Lockheed part number, SSB 2604.
I found 2 kits on Ebay here in the USA and have purchased those. They should be here by Saturday.
This forum is a great place to find the information to keep our Minis alive.
Jim
- Andrew1967
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Re: Cooper S Brake Calipers Rebuild Problems
Excellent .. glad to be of help Jim 
You’re right, this is a brilliant forum, no it’s the best forum, for our obsession !!

You’re right, this is a brilliant forum, no it’s the best forum, for our obsession !!
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- 850 Super
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Re: Cooper S Brake Calipers Rebuild Problems
The Minispares website show the caliper seal kit "S' and 10" wheel as GRK 5006 , Genuine Lockheed LK 12604.
Anyone use these kits for their caliper rebuilds ?? Curious as to the quality of the components ?
I have other calipers that I want to rebuild if the bores are smooth after dismantling.
Thanks
Jim
Anyone use these kits for their caliper rebuilds ?? Curious as to the quality of the components ?
I have other calipers that I want to rebuild if the bores are smooth after dismantling.
Thanks
Jim
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- Basic 850
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Re: Cooper S Brake Calipers Rebuild Problems
My kits from Minispares came in a box marked SHIFTEC HCK160. Please tell me the are ok.
Jim
Jim
- Andrew1967
- 1275 Cooper S
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Re: Cooper S Brake Calipers Rebuild Problems
https://www.ebay.co.uk/itm/401441256822
These are the ones I bought where the metal rings do not fit !
I actually only wanted a metal ring as I had genuine (NOS) Lockheed seal kits SSB2604 but one ring was missing. So I haven't tried the seals themselves.
These are the ones I bought where the metal rings do not fit !
I actually only wanted a metal ring as I had genuine (NOS) Lockheed seal kits SSB2604 but one ring was missing. So I haven't tried the seals themselves.
- timmy201
- 1275 Cooper S
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Re: Cooper S Brake Calipers Rebuild Problems
I bought a new Lockheed/920E kit which came with a Minispares sticker GRK5006. They’ve been working fine for the last year or so
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- 850 Super
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Re: Cooper S Brake Calipers Rebuild Problems
Purchased 2 Lockheed brake caliper kits, N.O.S., SSB2604 in their original boxes from ebay here in the U.S.A.
One of the metal retainers for the wiper seals was manufactured off center and is a sliver thin section and is NOT usable. The other retainers are proving very difficult to install in the calipers. Being too large in diameter. I must now purchase additional metal retainers.
Minispares web site states genuine Lockheed brake caliper kits, GRK 5006. Has anyone used these kits for their caliper rebuilds ??
As stated earlier, I purchased kits from our supplier here and they were labeled Caparo AP Braking with a Minispares sticker on the boxes, GRK 5006
and made in the UK.
What are others using for their caliper kit rebuilds ?? Minispares ?? Somerford ??
What is the correct way to install the the metal retainers and wiper seals ?? I must be missing something !! This should not be this difficult and frustating.
Thanks for your help.
Jim
One of the metal retainers for the wiper seals was manufactured off center and is a sliver thin section and is NOT usable. The other retainers are proving very difficult to install in the calipers. Being too large in diameter. I must now purchase additional metal retainers.
Minispares web site states genuine Lockheed brake caliper kits, GRK 5006. Has anyone used these kits for their caliper rebuilds ??
As stated earlier, I purchased kits from our supplier here and they were labeled Caparo AP Braking with a Minispares sticker on the boxes, GRK 5006
and made in the UK.
What are others using for their caliper kit rebuilds ?? Minispares ?? Somerford ??
What is the correct way to install the the metal retainers and wiper seals ?? I must be missing something !! This should not be this difficult and frustating.
Thanks for your help.
Jim
- Andrew1967
- 1275 Cooper S
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Re: Cooper S Brake Calipers Rebuild Problems
That's bad news Jim,
I fitted the seals to the rings and then the rings/seals to the callipers.
The rings would just start to enter the groove all the way around and then with a socket of the correct size, a gentle tap around the perimeter soon had them fitted home.
I fitted the seals to the rings and then the rings/seals to the callipers.
The rings would just start to enter the groove all the way around and then with a socket of the correct size, a gentle tap around the perimeter soon had them fitted home.
- Peter Laidler
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Re: Cooper S Brake Calipers Rebuild Problems
Andrew is dead right. The secret, as with all press-fit items is that they are pressed in dead square with the female - or caliper. The BEST way to do it is to separate the caliper halves, square-up and press in using a vice or press and press the seal and retainer in using a block of hardwood. Works for me every time. That said, I'm no pro, only ever having done it half-a-dozen times in my life.
Last set, I just put a small chamfer around the outer edge of the lip of the retainer and it slipped in like a well worn sea-boot!
Last set, I just put a small chamfer around the outer edge of the lip of the retainer and it slipped in like a well worn sea-boot!
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- 998 Cooper
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Re: Cooper S Brake Calipers Rebuild Problems
I've rebuilt two pairs of calipers using the GRK5006 repair kits from Minispares recently without any problems.
fit the piston seals and push in pistons leaving them high to locate the tooling, fit the wiper seals into the metal retaining rings and slide onto the piston, fir the tooling over the piston and press them in. As Peter says it's a lot easier with the caliper split.
Fit new seals 17H8764 and bolts.
If you weren't so far away I'd lend you the tooling!
fit the piston seals and push in pistons leaving them high to locate the tooling, fit the wiper seals into the metal retaining rings and slide onto the piston, fir the tooling over the piston and press them in. As Peter says it's a lot easier with the caliper split.
Fit new seals 17H8764 and bolts.
If you weren't so far away I'd lend you the tooling!
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- 850 Super
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Re: Cooper S Brake Calipers Rebuild Problems
1071 Bob, Thank you for your kind offer to loan me your tooling. Yes, I am too far away. Your pictures and instructions were very helpful !!
Did you make the caliper seal tool?
I did purchase a piece of steel pipe 2" OD X 1.760 ID. I have cutoff a 2" long section which I squared and beveled and deburred the ends.
I have installed 2 retainers and seals in one caliper which has been split, cleaned and painted. Tool did work well.
Now will have to purchase another GRK 5006 caliper kit to obtain the 2 needed retainers after bending and distorting 2 previously. Unfortunately the suppliers here have been out of stock for some time.
Thanks to all for your help!!
Jim
Did you make the caliper seal tool?
I did purchase a piece of steel pipe 2" OD X 1.760 ID. I have cutoff a 2" long section which I squared and beveled and deburred the ends.
I have installed 2 retainers and seals in one caliper which has been split, cleaned and painted. Tool did work well.
Now will have to purchase another GRK 5006 caliper kit to obtain the 2 needed retainers after bending and distorting 2 previously. Unfortunately the suppliers here have been out of stock for some time.
Thanks to all for your help!!
Jim