Disc Brake Shimming

[fishyboy]

Hi all,
I’ve been trying to fit a pair off BCC Pembury upgraded 4-pot aluminium callipers (> Austin Healey 3000 (Mk1 BN7 & BT7) Front Brake Caliper Upgrade Kit <) to my 1961 BT7 and I am experiencing some fitting issues.

Having removed the original Girling 14 callipers, which were perfectly centered on the disc (photo 1), the new callipers are offset to the right by 5-6mm and require 2.8mm of shims (2x0.9, plus 2x0.5mm) to bring the callipers close to being centered (photos 2 &3).

I am slightly concerned about needing 2.8mm of shims to center the discs. Is this acceptable?

Phil

 

[gonzo]

Since the pads will essentially "float" with the small mm gap taken up by the caliper piston(s), would that small distance be a significant concern? Check fitment with pads loaded and calipers working.

 

[Rob Glasgow]

Phil, I am interested in your project as I am considering converting to those calipers for my BT7. I have the stock set up and while it's served me well for over 60 years, I have always thought an improvement in the braking would add some comfort. I don't have a servo but I did install EBC Greenstuff brake pads that seemed to help.
I would be interested in your review of these calipers once you're done. Did you start with a stock non-servo system? Any other brake upgrades beyond the new calipers? Please let me know.

 

[fishyboy]

Hi Rob,
My setup was all original - standard Girling 14 calipers, standard pads and no servo. I did put on the braided flexi-hoses about 8 years ago, which seem to firm up the pedal but I have now reverted back to the standard rubber flexi-hoses. Apart from the flexi-hoses the only upgrade is the calipers so it should be a fair test.
Phil

 

[Rob Glasgow]

I went with braided lines about 5 years ago also. Was there a reason you went back to rubber lines with this upgrade? I’ll be interested to hear your thoughts on the new calipers. How long do you expect it will take you to finish the conversion?

 

[BobHaskell]

I went with braided lines about 5 years ago also. Was there a reason you went back to rubber lines with this upgrade? I’ll be interested to hear your thoughts on the new calipers. How long do you expect it will take you to finish the conversion?

One advantage of the rubber lines is that you can temporarily squeeze them shut. Closing off the one that attaches to the rear axle can isolate a problem to the front or rear brakes.

 

[Bob_Spidell]

O-T, a little: I recently stumbled across these at Harbor Freight, something I hadn't seen before (NFI):

Fluid Line Clamp Set, 4 Piece

Amazing deals on this 4Pc Fluid Line Clamp Set at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

They're a little fiddly to use, but I like the way they apply pressure evenly. I used the big one to clamp a 2" return line for a high pressure hydraulic pump on a tractor, which would otherwise require draining 5 gallons of fluid to not dump it on the floor. They also have a Vise-grip-like clamp, but it's a bit ungainly.

 

[BoyRacer]

Yes, you can safely use shims (spacers) to center your calipers.

 

[malbaby]

That's a lot of money for calipers that are not designed to fit properly.