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Rear Disk Brake Conversion
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stevebn2bj7
Jedi Warrior
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I have used their kit once and will likely use it on the next project (bn7). I find that the stopping is improved a good deal. Never having driven a BJ8 with the booster I can't compare it to that but it stops about as good as my modern car. The downside is that there is a good deal of fabrication you will need to complete. The axle flanges need to be trimmed a bit but that only takes about an hour with a grinder. The hard part (for me) was the e-brake assembly. You either need some good machine tools or have a machine shop fab the items required. After all that the e-brake is mostly useless, it will hold the car on a flat surface but does not have enough pressure to keep it on any incline. If I tighten the adjusters any more it would drag the e-brake pads too hard. I may try to work on that some more this coming year. The calipers are usually available locally or on Ebay. The other alternative is to narrow a Ford rear end but I think the cost would be at least equal and the difficulty level even higher. After all that, I will likely use theirs again.
Having had to use my e-brake to stop a couple of times when the brakes failed (fluid leak once, & PO failure to install a cotter pin in the clevis pin that attaches the brake pedal to the MC), I have found that the e-brake was essential. Maybe, I will just get by with the drum brakes at the rear. Thanks.
You might find the Cape International kit to be more complete than the kit from DWR. There is still a fair amount of grinding
to do primarily on the calipers with minimal on the axle
flanges. Some minor milling with be nessary on the mounting
sites on the calipers as well. The emergence brake fittings
are are a piece of cake although the brake rod fitting on the
right side may need to be rebuilt. Using the Cape kit the
caliper puston volumes are such that there is not need to add a proportioning valve to the brake circuit. As to stopping, on the initial test on my BJ8 in a panic stop from 60 mph - straight, correct attitude, and crisp.
to do primarily on the calipers with minimal on the axle
flanges. Some minor milling with be nessary on the mounting
sites on the calipers as well. The emergence brake fittings
are are a piece of cake although the brake rod fitting on the
right side may need to be rebuilt. Using the Cape kit the
caliper puston volumes are such that there is not need to add a proportioning valve to the brake circuit. As to stopping, on the initial test on my BJ8 in a panic stop from 60 mph - straight, correct attitude, and crisp.
john_j
Jedi Trainee
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This isn't my personal experience, but when a club member suggested rear discs, someone who has a company that re-builds A-Hs, including rally cars said it's a waste of time. Sorry, I can't recall the reasons, but presumably it's because 90% of the stopping power comes from the front of the car anyway, so uprating the back brakes doesn't make much difference.
When I changed my Sprite front brakes from 7" to 8" what happened was that it stopped much faster, throwing the weight forward more, and made the BACK wheels lock more easily, so if I had improved the back as well (8" were used there in the 50s) it wouldn't have helped stopping, just mad ethe back lock even more easily - useful for handbrake turns, but not for much else.
When I changed my Sprite front brakes from 7" to 8" what happened was that it stopped much faster, throwing the weight forward more, and made the BACK wheels lock more easily, so if I had improved the back as well (8" were used there in the 50s) it wouldn't have helped stopping, just mad ethe back lock even more easily - useful for handbrake turns, but not for much else.
jollyroger
Jedi Trainee
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I have heard that the rear disc assembly from a Jag MKII saloon will fit perfectly on a Healey.
Would be nice to know who in the UK you are referring to as
hearsay means little. The proportion of breaking on most big
Healeys is approximately 54 to 56% front the remainder from
the rear. The advantage of disc brakes on all four corners
proportionally more effective breaking surface to that of
drums with the addition of less potential fouling from leaking fluids something the haunts drum brakes, especially leaking rear axle seals.
Traditionally when big Healeys were rallied by BMC competition division these cars were fitted with disc brakes.
hearsay means little. The proportion of breaking on most big
Healeys is approximately 54 to 56% front the remainder from
the rear. The advantage of disc brakes on all four corners
proportionally more effective breaking surface to that of
drums with the addition of less potential fouling from leaking fluids something the haunts drum brakes, especially leaking rear axle seals.
Traditionally when big Healeys were rallied by BMC competition division these cars were fitted with disc brakes.
The calipers which DWR suggests for their kit can be obtained for XJS series of Jags, these are also used by Cape International. In reviewing an XKE manual and looking at his 2+2 XKE coupe, the rear calipers including the emergence brake calipers look like the ones the come with the Cape kit. My guess is since they are both Girling little has changed in their design. If you wish you can look at an article at the following site www.vintage-sportscar-touring.ca/technical.html the link on the page is fitting rear disc brakes.
john_j
Jedi Trainee
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[ QUOTE ]
The proportion of breaking on most big
Healeys is approximately 54 to 56% front the remainder from
the rear.
[/ QUOTE ]
I have no proof that what you say isn't true, but I'm surprised if it is - I would expect that the weight balance of the car would be 54 - 56% to the front, but when the brakes are on and the weight thrown forward, I would be expect the braking to be a higher figure for the front - I've just done a quick google but haven't found anything, I'll have another look later and report back.
The proportion of breaking on most big
Healeys is approximately 54 to 56% front the remainder from
the rear.
[/ QUOTE ]
I have no proof that what you say isn't true, but I'm surprised if it is - I would expect that the weight balance of the car would be 54 - 56% to the front, but when the brakes are on and the weight thrown forward, I would be expect the braking to be a higher figure for the front - I've just done a quick google but haven't found anything, I'll have another look later and report back.