Hi,
Our special has always had a mixture of brakes with the more modern girling type on the rear with pressed steel shoes and cast iron drums and the older type steel drums on the front with ally shoes. We assume it got the later brakes on the back when a rear axel was replaced for a later type. We would like to make the front and rear match so I have aquired the back plates and other brake parts but was wondering if the front stub axels would need to be changed as well or if they can be used as is or modified?
The Semi Girling backplates bolt onto the stubs. The best way forward would be to get later Semi Girling stub axles but others may know if the earlier stub axles can be modified. It’s interesting to note that when Austin moved to Girling they beefed up the radius arms to cope with the extra braking force. I know some box the radius arms to reinforce them.
07-02-2025, 07:48 PM (This post was last modified: 08-02-2025, 03:43 PM by Steve Jones.)
The earlier pre-Girling stub axles can be cut down and modified to take Girling type back plates but it's not by any means straight forward. By far the better and easier way is to swop them for Girling type stub axles that are a straight forward fit without any changes to the axle beam.
Are beefed up radius arms a good idea? When my radius arm was damaged in a front-end collision I was surprised how weak it was, but if made stronger it might have bent the chassis.
As far as I can tell, the radius arms themselves stayed the same or similar, but the attachment to the axle was modified to have two fixing points one above the other, rather than one. The idea was presumably to reduce the twist of the front axle beam under braking torque, which tends to act against the brake cable tension and partially lets the brakes off. If Austin saw fit to do this mod, you can be pretty sure it was needed.
The later (Girling) radius arms were deeper than the earlier ones and also had an extra fixing point to the front axle (as John notes above). However I think the main trick is to try not to run into anything solid...
Yes, the later ones are more robust and have two fixing points. As I understand it the merit of this is in reducing axle rotation (which tends to release the brakes) more than anything else.
Having two fixing points on the radius arms means that the castor cannot change. With the singlr fixing the radius arm can twist in the axle which alters the castor angle which in turn makes th steering more twitchy.
Frequentflyer, may I suggest you enter “radius arm comparison” in the search box. If you read down the first page you will find a quote from an old post of mine which discusses the result of mixing and matching chassis, springs and radius arms of different specifications - which will save me typing it all again! Hope it is of some use.
(08-02-2025, 03:30 PM)David Cochrane Wrote: The later (Girling) radius arms were deeper than the earlier ones and also had an extra fixing point to the front axle (as John notes above). However I think the main trick is to try not to run into anything solid...
Oh come on David, it meant you could sell me some bits :-))
