DISC BRAKES FOR DARRIN OR HENRY J

[darrin502]

Here is an article I got back in 2008 for the installation of Disc Brakes on a Henry J.
I have never tried this so I cannot vouch for it but I thought it was interesting.
I hope it is helpful for someone. It looks like it uses over the counter parts.
Lee

[njpatera]

Question: I haven't gotten to the frame/brakes yet on mine, but for the Darrin is it just HJ suspension using the full size Kaiser drum/Spindle? or is it all Full size suspension?

[darrin502]

It is the same as HJ just uses the full size Kaiser 11" brakes, drums and backing plates. The spindles are the same.
Lee
 

[njpatera]

Thank you!!!

[pjkaiser]

IMHO, I don't believe the Darrin needs disc brakes.   I drove my Darrin for three years, on the freeways at speed, etc. and did not have a problem stopping even at those speeds.   The 11" drum brakes provide more than enough braking for a car that is approx. 2000 lbs.    I don't know about the Henry J, since I do not own one.   

I was going to upgrade my brake system with my restoration and decided against it.   I will use Silicone brake fluid (Dot 5) as was done in my Traveler when it was restored approx. 30 years ago by Harvey Hedge****** and is still going strong and working fine.

[darrin502]

You are 100% correct about the Darrin brakes. As light as that car is 4 wheels with 11" brakes stops it just fine.
The HJ only has 10" brakes and is much heavier so a conversion to 11" Kaiser brakes or disc may make sense.
Lee

[joefrazer]

Both my Darrin and Henry J stop just fine using the brakes they were born with. A swap to disc would probably help if an engine transplant was done. I do think a dual master cylinder would be a big safety benefit though.

[Corsairdeluxe]

Mac Wells tried that conversion shown above. He had to remove it due to warping discs.

[darrin502]

Wow thanks for the info.
That’s what this thread is about.
Lee

[Terry T]

nice that this info is in its own thread vs being embedded  in some other non-related thread which is so common

when threads start going off the rails, we should all be bold enough to stop it and start a new thread

offtimes, those that change direction get offended when that is brought to light

[MarkH]

Mac Wells tried that conversion shown above. He had to remove it due to warping discs.

I notice the article doesn't mention removing the 10lb residual pressure valve from the front of the drum brake master cylinder. Calipers only require 2lbs residual pressure and won't fully release at 10lbs. That may have been the source of the heat that was warping his rotors.

[HJ-ETEX]

Residual Pressure:
That is an important point.
Many people are unaware that drum brakes have a residual hydraulic pressure and there is a check valve in the master cylinder for that purpose. Disk brakes don't have such a requirement. It is easy if you have a dual master cylinder because 1 side can have a check valve for the rear drum brakes.
As I understand it, Crosley Hot Shot and Chrysler Imperial had disk brakes in the early 1950s, but Studebaker had the 1st large scale US offering of disk brakes on their 1962 cars. The supplier was Bendix who was making a licensed Dunlop (Jaguar) system. Studebaker used a single reservoir master cylinder and solved the residual pressure problem by using a 1/2" wheel cylinder in the rear! These all had vacuum boosters and the unit is a quite recognizable "bee hive" shape that was not used on the power assisted drum brake cars. I suspect the assist was higher on the  bee hive unit.
I have worked on one of these equipped cars and I wasn't impressed.