After years of sterling service my Felicia failed its MOT today as the O/S rear brake is at 20%. The MOT tester said the handbrake works fine, but the footbrake doesn't on one side, which points to hydraulics?

 

After putting my Scenic through the MOT yesterday and costing me £170 to do that, I'm reluctant to hand over more cash for them to fix my Skoda, so I'm collecting the car today in order to have a look, but what am I looking for? The tester says the brake area is dry, no leaks he cab see, so could it be a seized piston?

 

Any pointers would be great.

 

thanks

yes possibly a siezed piston, fortunately they arent too expensive for those, but it is a bit fiddly taking the rear brakes apart.

Thanks Tom. ECP sell the piston for £8, but until I get the car back I don't know how tricky it will be.

It will  likely be not :sun: when I'm on the drive tackling it, so will be a PITA, but it is the only MOT failure it's had in 4 years.

Sounds like the case. Get the drum off and hold the shoes with a couple of pry bars so the wheel cylinder doesn't get pushed right out if it does work, then get an assistant to press the brakes and watch what happens.

 

Obviously, it's always better to strip the brakes down and clean and regrease all the moving bits, but if time is against you, it is possible to change the wheel cylinder with the shoes in place. Pry the hoes apart just enough to clear the cylinder and use a suitably lengthed double-ended spanner to hold them apart. 

 

Don't forget to rebleed the brakes, at the very, very least, on the wheel you change the cylinder on. 

how much did the mot garage want to charge to do the job? it cant be much surely?

Thanks for the tip Steve, I'll try to get my little helper on the case.

 

Tom, when I asked the MOT tester to check it for me, I got the sucking air through the teeth response and as he'd already taken over 2 hours to do another reasonably simple job, I wasn't prepared to shell out even more money this week. Possibly biting my nose off to spite my face, but I've got the car back now and will look at it tomorrow.

 

It's been a while since I messed with drumbrake pistons, but I'll post back what I find.

20% is very good for a single rear brake, did he mean 20Kg, which is quite poor?  You should be able to replace the cylinder without having to dismantle the shoes too much, just be careful not to twist the brake pipe when undoing it.

He may have meant 20kg, he just said 100 on one side and only 20 on the other and I assumed it was %.

with such asymetric braking, your car should spin like a spintop when you brake hard.

is that the case?

no i doubt it, the rear brakes barely do anything, my guess is you would never even notice

You're right tom, I never even noticed even when  I had to stop very quickly on a bend the other day. Straight as an arrow.

well then... if that's the case we can get rid of rear brakes alltogether and use them only for handbrake.

OR your rear brakes are both good or both bad and the garage fooled you.

OR your rear brakes are both good or both bad and the garage fooled you.

No chance of that when the brake efforts are measured on a calibrated, VOSA approved brake testing machine.

 

Do vehicles in Russia undergo an annual road worthiness test?

It was a seized piston on one side of the cylinder. 

I was rather surprised not to find new bolts in the box, as the old ones were very rusty after 13 years. The allen key holes were not one size or the next, so I had to tap in a hex bit to undo them. Then I had to elongate the holes in the backplate to accommodate the new Pagid cylinder as it was just out of line. There were no slots on the pistons for the shoes ends to locate into either. Otherwise, not too bad. A one man bleed kit and help from my daughter, who can't wait to get beyond the wheel and drive,  made the job much easier.

 

Thanks all.

Do vehicles in Russia undergo an annual road worthiness test?

no, we still live underground or in caves and we brake dragging the heels on asphalt.

 

Do vehicles in Russia undergo an annual road worthiness test?

In Russia you don't drive the car, the car drive you.

well then... if that's the case we can get rid of rear brakes alltogether and use them only for handbrake.

OR your rear brakes are both good or both bad and the garage fooled you.

If a normal sized car is unloaded, the rear brakes will generally provide less than 20% of the total braking effort. Not enough for you to be able to feel their effect, but still worth having to reduce the stopping distance and to hhelp hold the vehicle straight if one front brake locks up.

  A customer was moaning at me about his brakes so I told him to stop it.