16 replies to this topic

[Lenhamracer]

Hi

 

I need new brake calipers for my 7.5“ front brakes. Is there a big difference between the minispares calipers and the AP calipers which are also offered by minispares?

There is a huge price difference and I tend to the minispares calipers:

http://www.minispare...65.aspx|Back to

 

Thank you very much

 

Thomas

[Cooperman]

I have the Mini Spares 7.5" brake calipers on my 1990 Cooper historic rally car and they are ok.

[Quinlan minor]

I've had the Mini Spares 7.5" on mine since 2019, 10,000 miles, no complaints.

One was a little sticky from new, but was replaced immediately by Mini Spares.

[Lenhamracer]

Thank you for your comments, I have now checked my old calipers and they seem to be original Lockheed painted red by someone but there are already stainless steel pistons build in. Might be worth to put new seals in and give it a try. Or I keep them and get 2 new ones from minispares. 

[Lplus]

Thank you for your comments, I have now checked my old calipers and they seem to be original Lockheed painted red by someone but there are already stainless steel pistons build in. Might be worth to put new seals in and give it a try. Or I keep them and get 2 new ones from minispares. 

If you can get the old pistons out and check they really are good stainless then new seals makes plenty of sense.

[Cooperman]

Just blow the pistons out with compressed air. I always split the callipers into two parts after blowing the pistons out. The existing stainless pistons should be fine, so just fit a new set of inner and outer seals. The outer seals can be a bit difficult to fit, but just do it carefully and it'll be fine. Use a new O-ring in between the two halves and torque the bolts joining them to 45 ft.lbs. and use a bit of Loctite.

[Lenhamracer]

Thank you very much again. I have blown out the pistons and have attached some pictures. May be they are not perfect any more? There is some pitting I think. What would you do?

 

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[Quinlan minor]

I think they're worth a set of seals.

[Cooperman]

If you can micro-polish the pistons and get out any imperfections they'll be fine. Otherwise, just buy a new set of stainless steel pistons and new seals.

[super6al]

Just blow the pistons out with compressed air. I always split the callipers into two parts after blowing the pistons out. The existing stainless pistons should be fine, so just fit a new set of inner and outer seals. The outer seals can be a bit difficult to fit, but just do it carefully and it'll be fine. Use a new O-ring in between the two halves and torque the bolts joining them to 45 ft.lbs. and use a bit of Loctite.

I've just done this on my 8.4 brakes and it's easy enough to do. Make sure every thing is super clean including the fluid passage ways in the caliper - remove the bleed nipple. I used pipe cleaner brushes. The hardest part was fitting the metal retaining ring for the outer seal. It's very thin metal and easily damaged. Looking at your calipers, the rust will need removing where both seals sit especially the outer seal otherwise the retaining ring will be difficult to install. I also found there was a slight lip on the ring where it had been stamped during manufacturing. I used a soft stone in a Dremel to lightly remove the lip. I then used a large washer (or anything flat & large enough to cover the diameter of the ring). Make sure the ring is level with the caliper surface & a short hammer blow should be enough to seat it. 

[Cooperman]

Yes, those outer dust seals can be a right pain, especially if you slightly bend the lip when trying to fit them. That's one reason why I always 'split' the callipers into two halves as it make fitting the dust seals much easier. Use either rubber grease or a smear of normal grease around the edge of the dust seals, but wipe off any excess after fitting.

[Lenhamracer]

Thank you very much, I have now ordered the parts at Minispares and will get them next week. I will keep you updated...

 

By the way, I have another question. I am running an LSD from Swiftune and although it is much more drivable compared to the old salisbury LSD it is still hard in tight bends...

I was thinking of going to a quaife which seems to be the best option.

Is it possible to change the diff without removing the gearbox?? I would keep the ratio. I have a big selection of crownwheels and pinion for both options.

Would it be possible to just change the crownwheel ( as I would need the standard one for the quaife and not the LSD type) with the same gears?

 

Thank you very much

[Cooperman]

You can't change the diff with the engine in the car. It might be possible to cut a big access hole in the bulkhead and fit a cover plate, but that might detract from the structural integrity. Using straight-cut drop gears does enable the overall ratio to be changed slightly for different circuits, but not by much.

Crownwheels and pinions are matched items and can't be mixed.

Personally, having rallied Minis over several decades, I can never get on with LSD's. I've tested several competition Minis, but really struggle. However, for racing I do know that they are essential although for rallying they are not ideal.

[GraemeC]

All as Cooperman says, engine out. But to add - you don’t need to remove the gearbox from the block.

[Lenhamracer]

That was may be a bit misunderstandable. I  meant with the engine out of the car. As far as I remember the diff has a 64 crownwheel and 17 pinion. The crownwheel is the lsd type. Can I use a diff with a standard 64 crownwheel or do they need to be used in matched sets?

Thank you very much