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Drum brake 110 salisbury disc brake conversion

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#1 Guest_diesel_jim_*

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Posted 09 February 2007 - 09:52 PM

OK, so finally i've finished doing the axle conversion (well, 99%... still got to fit the mud shield thingies) but here's the main article...enjoy! :D

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:

Attached File  HPIM2769.JPG   418.68KB   633 downloads

Next, you need to refit the stub axles, with new joint washers:

Attached File  HPIM2770.JPG   478.24KB   647 downloads

Here I’ve fitted the caliper bracket in position too, I was jumping ahead of myself at this stage! :angry:

Attached File  HPIM2773.JPG   376.41KB   714 downloads

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:

Attached File  HPIM2783.JPG   358.92KB   485 downloads

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:

Attached File  HPIM2786.JPG   418.73KB   443 downloads

To this:

Attached File  HPIM2787.JPG   304.29KB   387 downloads

To this:

Attached File  HPIM2788.JPG   242.21KB   343 downloads

To this:

Attached File  HPIM2789.JPG   333.97KB   376 downloads

To this:

Attached File  HPIM2790.JPG   365.27KB   301 downloads

To this:

Attached File  HPIM2791.JPG   358.78KB   243 downloads

To this:

Attached File  HPIM2792.JPG   454.46KB   273 downloads

And with a bit of paint, to these:

Attached File  HPIM2802.JPG   448.62KB   421 downloads

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:

Attached File  HPIM2793.JPG   365.95KB   611 downloads

and with the caliper bracket:

Attached File  HPIM2794.JPG   413.1KB   662 downloads

Different length bolts can be used to hold the stub axles and caliper brackets in place, like this:

Attached File  HPIM2776.JPG   346.4KB   617 downloads

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:

Attached File  HPIM2804.JPG   368.55KB   587 downloads

Next is the assembly of the hubs. Pretty straight forward this, 5 bolts hold the disc in place:

Attached File  HPIM2777.JPG   282.78KB   490 downloads

Attached File  HPIM2778.JPG   345.83KB   388 downloads

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:

Attached File  HPIM2779.JPG   402.57KB   467 downloads

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)

Attached File  HPIM2806.JPG   481.17KB   447 downloads

After fitting the lock tab and the locking nut, you have this:

Attached File  HPIM2799.JPG   454.25KB   423 downloads

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 (this was pure luck…. I mean, pure engineering skill! :rolleyes: )

With the spacer in place, there is a few millimeters of space between the brackets and the inside of the disc:

Attached File  HPIM2781.JPG   314.51KB   518 downloads

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.

Attached File  HPIM2797.JPG   345.13KB   452 downloads

With pads:

Attached File  HPIM2798.JPG   426.42KB   311 downloads

Attached File  HPIM2810.JPG   369.28KB   292 downloads

Attached File  HPIM2808.JPG   356.2KB   312 downloads

Attached File  HPIM2812.JPG   315.45KB   260 downloads

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:

Attached File  HPIM2823.JPG   344.87KB   250 downloads

Attached File  HPIM2825.JPG   377.79KB   331 downloads

And finally, the addition of a splash more of black hammerite, some brake pipes and clips, and a diff guard…. Job done!

Attached File  HPIM2836.JPG   313.52KB   392 downloads

Attached File  HPIM2837.JPG   315.78KB   320 downloads

Attached File  HPIM2840.JPG   338.62KB   464 downloads

Attached File  HPIM2841.JPG   448.02KB   432 downloads

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

#2 white90



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Posted 09 February 2007 - 10:13 PM

Excellent thread now a tech archive item

Keep this forum independent click HERE.

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