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AH 3000 rear disc brake conversion

Asuny64BJ8

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Researching converting my rear drum brakes for AH 3000 BJ8 to disc brakes. If anyone has any information or suggestions please let me know.
Thanks

Daniel 1964
 
welcome! can I suggest you repost your question in the Austin Healey section - not everyone looks here as it is the introduction page.
 
Hi Daniel, I'm moving this thread to our Austin Healey forum (I'll leave a "re-direct" marker in the New Members Intro forum) If you're reading this then you have been magically transferred to the AH forum.

Please do go back to the "New Members" forum and post an introduction of yourself.

Basil
 
Conversion kits are available from:

Denis Welch, https://www.bighealey.co.uk/austin-healey/healey-brakes/brakes-general?page=2. These are the ones I have.
AH Spares, https://www.ahperformanceparts.co.uk/performance-parts/Brakes-Rear/default.aspx
Steve Gerow, a member of this forum (steveg), https://pbase.com/stevegerow/healey_rear_disc_setup. According to his signature, he sells a complete kit, including a part that makes the emergency/parking brake work properly.
Thank you guys, this new info is very helpful
Thanks
Daniel
 
Hi Daniel -

I have rear discs on my '57 vintage racer, but find the drums provide plenty of braking power with the right pads on my '65 Bj8 for street perfromance driving. I did upgrade to balanced and vented drums which also eliminated the scuttle shake that occured at 60 mph.

Wheel 1.jpg


 
John, Thanks for the mention. Since it's relevant, guess I'm allowed a mild self-plug.

The kit's the most complete; the installer needs to supply their own calipers, e-brake rods, hard lines and proportioning valve.

RearDiscThruWheel.JPG

DiscRotorKitComplete0616.jpg
 
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Ventilated and balanced rear drums are an excellent alternative to modifying originals. I also have them installed on my BJ7. Considering a 4 pot caliper upgrade for the fronts now. GONZO
10a937bf-2288-4027-a5ec-2e753aadac6f-1.jpg
 
Gonzo - you won't be sorry you converted to 4-pots. Make sure the calipers fit your smaller (Type 14 IIRC) adapter plates. I believe they're available in both Type 14 and 16 bolt centers.

Edit: what selection of pads is available for the AHspares calipers? Do they use a pad design from a common car?
 
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Cpnsidering the nose heavy condition upgrading the front is the place to spend your money. The rear brakes probably do not do a lot of the braking. Adding a lot of braking to the rear and not upgrading the front will cause a big balance problem.
 
Cpnsidering the nose heavy condition upgrading the front is the place to spend your money. The rear brakes probably do not do a lot of the braking. Adding a lot of braking to the rear and not upgrading the front will cause a big balance problem.

Agree. That's why the proportioning valve is necessary with the addition of rear discs.
 
Nobody asked me, but that's never stopped me before ... I have/had several cars with 4-wheel disks. None of them have, IMO, anything more than barely adequate parking/emergency brakes; both my Healeys, with the big drums in back--front, too for the BN2--have excellent parking/emergency brakes. Just sayin' ...
 
Nobody asked me, but that's never stopped me before ... I have/had several cars with 4-wheel disks. None of them have, IMO, anything more than barely adequate parking/emergency brakes; both my Healeys, with the big drums in back--front, too for the BN2--have excellent parking/emergency brakes. Just sayin' ...

With the stock setup, the rear drums are true emergency brakes, in that they will actually stop the car.

John Turney and I (and some others) have added dual master cylinders to divide the fronts from the backs, giving an emergency braking setup.

My adapter plates augment the e-brake force and give a better e-brake handle angle.

EbrakeLever.JPG
BrakePlatesFinal.jpg
 
When I installed my front and rear discs, I had a conversation with Denis Welch about the front/rear balance. He said with the 1.5" piston diameter rear calipers and the 2.125" piston front calipers, proper brake balance can be obtained with proper pad selection.
 
When I installed my front and rear discs, I had a conversation with Denis Welch about the front/rear balance. He said with the 1.5" piston diameter rear calipers and the 2.125" piston front calipers, proper brake balance can be obtained with proper pad selection.

John,
Did you pursue that avenue and if so, did you verify it with a panic stop?

FWIW before installing the proportion valve, I did a panic stop with my then-new 4-wheel discs and the car about swapped ends.

Richard Mayor (Boy Racer) gave me an easy method of setting the proportioning valve with the car on jackstands, which I'd be happy to pass along to anyone who wants it. The valves are around $40 and installing and adjusting them is a one-time-only task.

The DW system would call for different pads front and rear. If one changed front pads then maybe the rears would need to be experimented with for each change. The proportioning valve would call for the same pad composition front and rear.

I've been using the Centric Ceramic pads for several years with good unboosted pedal pressure and absolutely no squeaking.
 
My pointr egarding the rear brake conversion is that the drum brakes are probably sufficient and the dollars should be spent on improving the front brakes.
I am guessing that the fronts do 85-90% of the stopping.
 
John,
Did you pursue that avenue and if so, did you verify it with panic stops?
Yes, they worked fine until I felt I needed to rebuild the brake system after 12 years and I put in the wrong master cylinder. My new rebuild includes the correct MC. I have to look through my records and find the correct pads (good ones in front, not so good in back).
 
My pointr egarding the rear brake conversion is that the drum brakes are probably sufficient and the dollars should be spent on improving the front brakes.
I am guessing that the fronts do 85-90% of the stopping.
You are correct, but rear discs look cool and don't cause scuttle shake.
 
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