Truck brakes disc changing guide

Slidey

Was a little bored and was told to take my time with this job so decided to do a little tutorial. This was done on a MAN TGA 6x2 tractor unit but it is similar to any knorr bremse disc brake set up.

First off you need to secure the truck with wheel chocks as the handbrake will be off for long periods at a time. Jack the truck up and remove the wheels. Do NOT forget to use axle stands or something similar as a safety precaution.



A points to the half shaft studs, once you remove the wheel these are taken out and the half shaft just slips out. Have a container at the ready to catch the small drop of gear oil from the axle.

B Points to the 14mm Allen bolts that secure the disc to the hub.

To make it easier on yourself, loosen these before you touch the brake caliper with the handbrake on, it will stop the assy from moving.




Making sure that the air is up and the handbrake is off wind back the pistons in the caliper using the adapter that should be under the rubber boot and a 10mm spanner. Be careful, stop once the pistons are fully retracted, the adapter is designed to break if you go to far.



Making sure your air is still up and with the handbrake in the off position, take off the handbrake chamber shown here. It is held in place with 24mm nuts. You do not actually have to take it off but it makes an already heavy caliper a little lighter and easier to handle. It also means if the air goes down you can put it further back together before you have to start it.

Next take off the 6 27mm bolts that secure the caliper to the axle. Be sure to have something to rest the caliper on or else you will have to disconnect the wear sensor. You can see I have left it on a brake drum below



The arrow is point to the locking tab on the hub bearing nut. Tap this back before you start to undo the nut for to make life easier on yourself. Using the correct castle style socket take the nut off.

Once the hub nut and washer is off the hub assy is ready to come off. This needs to come off in one fluid motion. Do not shake this about too much. This is heavy so some may need a 2nd pair of hands.








Once the assy is on the ground all it took was a tip of a sledge and the 2 fell apart.

Installing is basically a reversal of removing. When the hub is going back on it is critical that it slides on straight and without shaking it from side to side. The 2 bearings are held together with a small clip. If you shake it around too much the clip can come off and if you do not realise you have done this at the time you will damage the clip when torquing the hub nut.

Plug

Thats good stuff Slidey I always wanted to know a bit about trucks. This is more or less the same process for the new transits with rear disks. Once the disk and hub are out we have to separate them by removing eight 50 torx bolts and then using the press. They are a few special tools that makes life easier.
A few pointers for that is the 44mm hub nut is 300nm and if it has the 51mm hub nut(more common) is 450nm of torque. Also the left hand side has a left hand thread.

-Corkie-

Good stuff Slidey. I will do a Hino 700 guide some day I have time..:)

volvoman480

Lovely job. Just goes to show how similar all modern trucks are now. That entire suspension set up and brake assembly is practically a carbon copy of the back of my Volvo. Most of the components are bought in. Knorr brakes, Haldex or Wabco driers, the list goes on and on......

Slidey

A lot of the stuff go braking and suspension is out sourced alright.

@corkie I haven't touched the wedge type brakes on the 700s. I believe they are sh1ty enough.

I had pics and all from doing scania shoes and drums. Showing stripping and re lining of the shoes as well but things didn't go to plan and I deleted all in disgust!

-Corkie-

Slidey wrote: »

A lot of the stuff go braking and suspension is out sourced alright.

@corkie I haven't touched the wedge type brakes on the 700s. I believe they are sh1ty enough.

I had pics and all from doing scania shoes and drums. Showing stripping and re lining of the shoes as well but things didn't go to plan and I deleted all in disgust!

They arent too bad but you can get an odd set that are a pure b1tch to do. I done a set 3 weeks ago and put the whole thing back together including wheels until I looked around and seen the spring on the floor....:mad::mad::mad:

Plug

-Corkie- wrote: »

They arent too bad but you can get an odd set that are a pure b1tch to do. I done a set 3 weeks ago and put the whole thing back together including wheels until I looked around and seen the spring on the floor....:mad::mad::mad:

Corkie I never knew you were a truck mechanic.

volvoman480

-Corkie- wrote: »

They arent too bad but you can get an odd set that are a pure b1tch to do. I done a set 3 weeks ago and put the whole thing back together including wheels until I looked around and seen the spring on the floor....:mad::mad::mad:

That's the kind of sh1t that makes put more sugar in my tea and regret that I ever gave up the fags.......

-Corkie-

Plug wrote: »

Corkie I never knew you were a truck mechanic.

I am not one actually..:pac: You have to know how to do these things when you own them..:)

volvoman480

-Corkie- wrote: »

I am not one actually..:pac: You have to know how to do these things when you own them..:)

I know that feeling.... The joys of motoring eh....

-Corkie-

volvoman480 wrote: »

I know that feeling.... The joys of motoring eh....

Ya and I forgot to say to Plug a very badly paid mechanic at that as you know your self..

volvoman480

Paid??? You get paid?????:(:(:(:( Where did I go wrong???