Drum brake 110 salisbury disc brake conversion
At long last! After decades (well, months) of me promising, here’s my tech article of how to convert a drum braked 110 salisbury rear axle into disc brakes.
Now, there are several ways to go about this, depending on what discs and what calipers you use. I suspect that the cheapest route would be to use range rover discs and calipers, as they’re pretty well obtainable anywhere for not much money. I chose to use the pukka 110 discs and calipers, for several reasons:
• I plan to fit this axle to either a heavily laden 110, or 130 if my “project heavily laden 110 or 130” plans come together!
• I won a set of genuine 110 rear discs on eBay for £12
• I won a LH salisbury brand new caliper for about £15
I’ll post the list of parts needed at the end of this article. The list depends on how anal or “perfect” you want to go. I chose the anal route… getting all the little plastic brake pipe clips and stuff together, just because I like the look of a proper job, and I don’t want anything breaking later down the line.
Anyway, here goes.
First off, you need an axle. There are two types of salisbury ones available. The 21S and 24S (this is the code that the axle serial number of the axle starts with… stamped on the back of the LH side of the tubing) 21S is “standard” and 24S is the Heavy Duty version. I think it’s some of the casing internals that are beefier, as the outside looks the same.
Mine is a 21S, but I think that they’re pretty strong even in this form.
So, sit the axle on some stands, support the nose of the differential and you can strip down the drum brakes. Remove the drum, the shoes, slave cylinder and rear anchor plate, and finally the stub axle, you should have this:
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Next, you need to refit the stub axles, with new joint washers:
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Here I’ve fitted the caliper bracket in position too, I was jumping ahead of myself at this stage!
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When I roughly fitted everything together, I thought that it would just be a “nut and bolt job”, of sticking the hubs and disc together, the caliper bracket and that was it. However, when I fitted it all properly, I found that the combination of early 90/110 front hubs (the sort that was fitted to axles with the 23 spline CV’s) and the 110 discs, it made the caliper bracket interfere with the disc, by about -3mm, so some kind of spacer was needed to move the bracket away from the disc. After a bit of measuring, and playing with washers as spacers:
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I found that the spacer needed to be 6mm thick., so armed with some 6mm plate, a drill, a center punch and hammer, and a couple of angle grinders (5” and 9”), I converted this:
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HPIM2790.JPG 365.27KB 314 downloads
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And with a bit of paint, to these:
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Phew! Not the neatest job, in hindsight a plasma cutter would have been much neater and quicker, but I haven’t got one, and my friend who has is about 40 miles away. But they’re plenty strong enough, and the “outside” edges don’t hinder their use.
These spacers mount between the stub axle flange and the caliper bracket, like:
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and with the caliper bracket:
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Different length bolts can be used to hold the stub axles and caliper brackets in place, like this:
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The two “middle” bolts can be longer, to allow lock nuts to be fitted. The outer two you can’t fit locknuts to, as there is a casting on the bracket for the fitting of the disc guard.
And when they’re painted,(and in position) they look like:
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Next is the assembly of the hubs. Pretty straight forward this, 5 bolts hold the disc in place:
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You can see the thickness of the 110 discs. They’re about 15mm, so easily capable of absorbing a lot of heat. Whilst these hubs were apart, I cleaned them, painted, and then fitted new wheel bearings and oil seals. (Details of how to install the new bearings can be found Here,courtesy of Mr Henson
Offer the disc/hub units onto the stubs like this:
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And using the original “spacer” washer things, they can be fixed in place:
( I can’t see that this spacer will be able to move at all. Once the inner adjusting nut is tightened then locked with the outer locknut, it’s not going to go anywhere. I considered filling the little empty void spaces with weld and grinding them down, but thought it wasn’t necessary)
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After fitting the lock tab and the locking nut, you have this:
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As there is no oil seal (like when the original drum brake setup was fitted) then these bearings will eventually become “oil lubricated” from the axle oil. Not a bad thing.
One of the advantages of this particular method of doing the disc brake conversion, is that you can retain the drum brake spec half shafts. I removed the rear diff cover (ages ago on another axle project I was playing with) and the splines engage into the sun gears within a 2mm of the original position, so no strength is lost by the shaft not being inserted enough (
With the spacer in place, there is a few millimeters of space between the brackets and the inside of the disc:
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Which is just the same space as on a “factory” axle.
Here with the caliper and half shaft fitted in place:
You can see that the disc is virtually in the center of the caliper.
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At this stage I’ve not fitted the disc guards (bought cheap from Billing a couple of years ago). I need to cut off the end of the caliper mounting bolts (the ones that havn’t got the locknuts on) as they protrude out by about 5mm too much and interfere with the guard going in place)
While I was doing this job, I copied the positions for the pipes and clips off of my 110 (Td5 with disc braked axle) so I put all the parts in the “factory” position. I also made up some HD spring retaining plates out of 4mm flat bar that I had kicking around.
There is a little “tag” type bracket that goes to the left of the diff casing. This supports the brake pipe and the breather pipe:
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HPIM2825.JPG 377.79KB 341 downloads
And finally, the addition of a splash more of black hammerite, some brake pipes and clips, and a diff guard…. Job done!
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All I need is a RH brake salisbury caliper…. Anyone got one lying around? Part # STC1268
The parts list for what I used is:
FTC3306 x2 caliper brackets
STC1268 RH caliper
STC1269 LH caliper
NTC7964 RH brake pipe
ANR2779 LH brake pipe
NTC8242 plastic pipe clips (x4)
NTC8242 metal “P” clip (for brake pipe)
Bolts for the stub axles:
There are 3 different lengths for each stub, the “short” ones, that only hold the stub axle in place, are M10x35
The “middle” length, that go through the caliper bracket but don’t have the locknut on, are M10x55
The “long” ones that go through the caliper bracket and also have the lock nut, M10x60
I also replaced the 10 bolts that hold the drive hubs in place, M10x45
The brass “T” piece is the same as for the drum braked pipes, so no need to change that (although it’s £11 if yours is missing!) part # NRC4251