Thread: Disc Brake Conversion.

I have a Discovery here I'm wrecking. I will make some time this weekend to take off a rear wheel and confirm that the discs are the same.

As for the caliper, it is definately a rear Discovery one. I have already confirmed with the part number stamped on the side.

Agrojnr is posting the new caliper bracket to me, I will confirm if it fits or not on the day it gets here.

On further inspection, it looks as though thick washers have been used between the plate and caliper to make it sit inline with the disc. I'm really liking Agrojnr's idea of making the initial plate out of 8mm (if we can get away with it) and having a secondary plate as a spacer for the caliper. I'll measure the total thickness at the caliper end when I have the plate.

When I think about it, the backing plate for the original drum brake assembly would definatley not have been as thick as 8mm, I've never heard of one of those failing.

Yep, a secondary plate and then tack-weld to the main-plate.

Will work like a charm.

so what's the details on fixing the disc to the hub?
and is there any chance of a cad drawing as I'm in New Zealand?
my trucks got a 200tdi and ive been toying with the disc brake ideafor a while you guys just seem to be a few steeps ahead.

Originally Posted by TJWA

..........When I think about it, the backing plate for the original drum brake assembly would definatley not have been as thick as 8mm, I've never heard of one of those failing.

They are closer to 3mm (although undoubtedly in Imperial units!), and I have never heard of one failing. But they have a lot more area, and they have various pressed ribs etc to make them more rigid, which this plate does not have, and are probably heat treated. Having said that, I would think that 8mm is quite adequate.

John

As I have said before I could always make the adaptor plates out of a higher grade (gr350 or bisalloy) the only problem with bisalloy is they have been known to crack so 350 grade would be better.

The spacer plate can be made in 1 piece so both bolt holes are joined if there is enough space

Adam

Originally Posted by boot

so what's the details on fixing the disc to the hub?
and is there any chance of a cad drawing as I'm in New Zealand?
my trucks got a 200tdi and ive been toying with the disc brake ideafor a while you guys just seem to be a few steeps ahead.

I could always send a set there or the cad dwg

Adam

Originally Posted by JDNSW

They are closer to 3mm (although undoubtedly in Imperial units!), and I have never heard of one failing. But they have a lot more area, and they have various pressed ribs etc to make them more rigid, which this plate does not have, and are probably heat treated. Having said that, I would think that 8mm is quite adequate.

John

My assumption about the differences between drum brake backing plate and disk brake calliper mount is the point loadings. As John says, in the drum brake the loads are diametrically opposite so the stress shared by the six bolts in the pitch circle. The disk brakes the stress is all on one side so the distributional forces would likely distort the mount on that side.

My guess the sums need to be done by an engineer familiar with metals.

I agree with John and Diana - get the thing properly checked by an engineer and certified, which will cost money but will give you peace-of-mind.

Brake modifications are definitely not something which can be experimented with on the public highway, especially if they break and someone dies!

Top work on the prototype Adam - looks beautiful!

Cheers Charlie