The smell of burning!

Overheated rear brake disc.

I was in a hurry the other day to get the dog to the vet. It was not until I was part way up the bypass that I realised that the handbrake had stuck on. Even though the hand brake leaver in the cab was completely off, the smell of brake linings was overpowering. It's just as well the vets was not too far, even so the back wheels were so hot you could not touch them. Just before we made the return journey I slipped under the van and pulled back the little arms that operate the handbrake on the back of the callipers. Man, they we tight! This does not bode well for those new wheel bearings that were fitted earlier in the year. A sticking hand brake is one of the reasons why the bearing failed in the first place!

 

Showing handbrake arm on Calliper

With the back of the van up in the air and both the wheels off, it is time to get to grips with sorting this problem out. On further investigation it turns out that the shaft that sticks out of the back of the calliper with the handbrake actuation arm on, has rusted tight. Even though there is a little rubber cup that sits between the calliper and the arm to protect the shaft from the weather. I believe this is its downfall because once the water gets behind the seal it remains there helping the rust to build up causing it to seize. 

 

Once the handbrake cable has been loosened you can remove the end of the cable from the arm more easily, with a bit of fiddling. To free the arm off you will need to tap it backwards and forwards with a medium weight hammer. Do not over do the amount of force you use when hitting the arm with the hammer. The idea is not to do it in one hit but to keep moving it up and down until the sprung loaded arm moves back to the off position on its own. When it feels like it has freed off enough to move it easily by hand, you need to check it's at the off position. If not, it is time to take a closer look at the spring. If the metal of the spring is pitted and heavily rusted it is possible that it has lost some of its tension. For the three or so pounds each it costs to replace these springs it is not worth messing about. Removing the spring from the arm is a bit annoying but straight forward with a pair of pliers.

Handbrake arm spring old and new

 

There is one last thing to do as a suggestion before you box it up and that is to get some white grease and push it in behind the little rubber seal that protects the handbrake arm shaft this will help to keep things moving and the weather out.

 

I have used this method on my van and so far, the hand brake has not stuck on again.

 

Related post   rear wheel bearing replacement.

 

 

 

Vauxhall Vivaro rear hub nut and brake dices replace

This post has been prompted by the lack of good technical information out there on the Vauxhall Vivaro, Primastar and traffic van and in particular the rear hub settings.

I recently had a rear hub bearing seize up, luckily the bearing had not welded itself to the stub axle. Which is all too common in this type of bearing failure.

I am surprised and concerned to find a lot of miss information on forums. The lack of this information is making a statement like: “if you don't know the torque setting for the hub nut just tighten it up as tight as you can and then put a scaffold pole on the Tee bar and do it up some more!”. This stratagem can be dangerous and will cause the bearing to prematurely fail again. Why? The rear hub bearing is of the taper roller type which means that if you do not set it up correctly it will bind on the runners causing it to overheat and seize. These are not like ball bearings which can be over tightened (which is not recommended) because there is not the same direct affect.

The specialist kit you need to do this job properly:

36 mm socket

1. A thirty-six-millimetre socket for the hub nut. Which is three quarter inch drive that you may step down to half inch.
2. A Tee bar.
3. An extension bar like a scaffold pole no longer than a meter for loosening only.
4. A torque wrench that can go up to three hundred Newton meters. Which are not that expensive. Please note that wrench is Six hundred millimetre long (half a meter) This is the optimum length for this weight of tightness.
5. Spanners and or sockets for the brake calliper mounting bolts of twenty-one millimetres.

300 Newton meter
torque wrench

Destroyed bearing.
Also shows ABS ring.

Be careful not to damage the wheel sensor. The hub nut should be tightened to two hundred and eighty Newton Meters which is surprisingly not that tight - about a quarter of a turn or so after it has been done up normally with a ratchet. The mounting bolts for the calliper cage- one hundred and eighty Newton meters- you should clean the threads with a tap before adding new thread lock and the wheel nuts are one hundred and forty Newton meters and don't forget to put a little bit of lube on the threads.

If you would like to ask any questions or add further to this post, please do.

Related post:   Sticking handbrake.