17 replies to this topic

[mini-obsessive]

I need to replace both of my rear radius arms as they are bent.. also the front has had a 12" conversion and the back are still on 10" drums..
How easy is it to replace the arms and change it to 12" drums on the rear. I do not have extensive mechanical experience but i would like to give it a go but if it is going to be too difficult then i do not want to bite off more than i can chew.

Also, what tools will i need on top of the obvious jack and spanners

Thanks
Tim

[GW]

the rear brakes are the same - no need to change them for larger wheels.

Couldn't help you with the fitting though as not done it myslef yet.

[midridge2]

what makes you think the radius arms are bent?

[lrostoke]

Biggest worry when changing radius arms is seized bolts.
Plenty of penetrating fluid is needed.

To remove

take off the wheel, remove shock absorber. disconnect flexbrake pipe off the radius arm. you will need to clamp the hose save losing all the fluid.

disconnect handbrake cable

Then there are four bolts that hold the outer bracket on, two are hidden and probably covered in dirt and mud. These are the ones that can snap.

One last nut is on the end of the radius arm where it goes through the subframe

problems that can happen, seized bolts snapping, brake pipes corroded may snap.
bleed nipples on brake cylinders can snap.

[GraemeC]

You don't need to disconnect thte brake hose, saving the hassle of rebleeding. Just remove the back plate with the slave cylinder and hose still attached & connected then tie it up securely out of the way whilst you swap the arm.

[midridge2]

You don't need to disconnect thte brake hose, saving the hassle of rebleeding. Just remove the back plate with the slave cylinder and hose still attached & connected then tie it up securely out of the way whilst you swap the arm.

what about were the flexi pipe joins the metal pipe and is connected through the bracket on the radius arm?

[mini-obsessive]

I know one arm is bent because my brother handbraked it into a curb before i bought it off him! Luckily this was the only damage caused!!

From what you guys have said it seems like something that i could deffinately get stuck into and sort out myself.. my only hold up is what happens if a bolt does snap?? any other ways to remove it or does it just need to be drilled out?

[lrostoke]

hang on though the brake pipe for the rear brake is attached to the radius arm via a bracket on the radius arm least it is on mine.
Flexi pipe male thread goes through bracket on radius arm, then rigid pipe from slave cylinder connects to that via a female fitting.



Shows bracket that the pipes should go through. Even removing backplate the pipe would still be connected to radius arm

just noticed midridge2 beat me to it

Edited by lrostoke, 28 June 2010 - 10:13 AM.

[reffle]

I know one arm is bent because my brother handbraked it into a curb before i bought it off him! Luckily this was the only damage caused!!

From what you guys have said it seems like something that i could deffinately get stuck into and sort out myself.. my only hold up is what happens if a bolt does snap?? any other ways to remove it or does it just need to be drilled out?

Before attempting to loosen the bolts, lightly hammer the bolt to loosen the grip of any rust and drench in penetrating oil. Don't put any pressure at all on them, this is one area that needs time!

I had to drill out one of mine that sheared, luckily the welded nut on the other side was accessible so I simply drilled out the bolt and ground down the nut, just used a new bolt and nut, the others are more difficult to sort out as they aren't accessible from the other side.

[AndyMiniMad.]

Mine during the refurb.



As you say the arm was bent by the wheel ramming the curb. I would suggest you check all the components as pictured. Something else might well be dammaged. The three bolts you can see between the brake shoes hold the back plate on to the arm. I fitted new bearings and seals while it was in bits even though nothing wrong with the old ones.

[GraemeC]

Good point reagrding brake pipe join - I was speaking from experience from doing mine the other week, but I have a braided hose from the slave to the subframe and hence no join. Apologies for poor info.

[midridge2]

a radius arm is very solid and takes a hell of a force to bend it, i would check the hub shaft first then the radius arm brackets for damage before thinking its the radius arms.

[mini-obsessive]

Sorry to be thick but where am i looking for hub shaft?? The brackets im sure i will find on my own though lol

[AndyMiniMad.]

Take a look at my picture. The hub shaft is the spindle which is in the middle of the black back plate. The hub is the greasy looking thing with the hole in the middle. this goes onto the shaft and then gets secured with the big castle nut and split pin. the brake drum then goes over the lot and is secured to the hub with the cross head screw. you can just about make it out in the picture. The big silver washer loking thing in the middle of the hub is covering the new bearing i installed. you cant see it because its packed with grease in the picture. The cup thing then covers the castle nut and stops dirt getting at the bearing. Youcan reverse all the above to dissmantle your hub and arm. And yes definately check everything for damage because if you bent the arm you will most likely have mullered something else aswell.

[mini-obsessive]

Thank you.. looks like im going to have a few busy nights after work this week!

Cheers for the help tho.. muchos appreciated