The gear jammers thread

I thought I'd open a new thread for anyone who has motoring or car maintenance problems.

Ask any question you like, I'm sure if I can't answer it someone will, if I don't know the answer there's a vast data-base I can look up for you.

I would include motor cycles too but we's all over the hill in that department, . . having said that, I was in a bike showroom yesterday having a nosey.

Also if you have any tips on cars or driving I'm sure we'd all like to see them.

Re: The gear jammers thread

Ok....

Is it possible to sand down brake discs if you've let the pads go down too far and they've been 'scratched' ?

I was getting some noise on breaking (like metal to metal sound!) and went into the garage and thought I'd only need pads but I needed discs as well! (Plus 2 new tyres!!)

Re: The gear jammers thread

Yes Azz, when they tell you they have to change the discs it comes as a shock doesn't it? The pads might be relatively cheap but the discs are not.

In fact you don't even need to go down to bare metal, the manufacturer sets a minimum thickness for the discs, this is partly so that the pads don't have too far to move to close on the disc, bigger distance = longer time = further travel before stopping.

In the case of Citroen it's about 85% of the new thickness which amounts to only a mm or so. I argued this with the Citroen garage mechanic and he agreed to let them go down to 75% which gave me another years use. I think the manufacturer deliberately set the % high so that (a) they will get more changes = more spares sold and (b) if they set the level too low and some wally had an accident he might sue Citroen, another reason why the cost of living keeps rising, makes you want to die sometimes doesn't it!!

Re: The gear jammers thread

Thanks Denis, do you have any experience of these new(ish) automatic gearboxes??? the ones that are basically clutchless manual gearboxes, I need to find out a bit more about them.

Re: The gear jammers thread

Yes it is Azz, provided the minimum thickness has not been reached, you don't sand them down, take them to an engineering machine shop and they'll skim them on a lathe for you at a reasonable price, . . less than the price of a new pair I might add.

Re: The gear jammers thread

The ones I've heard about are driven by belts and pulley wheels as opposed to a toque converter with transmission fluid. I'll find out more and let you know, what make of car are you talking about ? is it Audi by any chance, if so it could narrow the search down.

Re: The gear jammers thread

Thanks both - wish I knew that before going into the garage!

I normally go to an independent garage owned by a guy who's mother I know (so know he won't rip me off ) but as these breaks were making a noise and I just passed this big chain (called national garages or something) I thought I'd just pop in and ask how much some new pads would be. I knew it was metal on metal noise so guessed it might be the discs, but just wondered if they could have been 'skimmed' as I only got them last year or the year before!

I was under the impression that a light comes on in the dash when pads are getting too worn (I swear that's what happened last time! :-/).

Re: The gear jammers thread

Ah ha! . . they've only been on a year so I'd check to see if anti-squeal shims have been fitted, they go between the pads and the calliper piston, it's unlikely the pads have worn down to the metal backing in one year, . . the noise without shims is a high pitched squeal as opposed to a metallic grinding.

Re: The gear jammers thread

There are two types of braking callipers fitted to cars, the fixed type and the floating type, here's a couple of diagrams they'll explain it.

The fixed type, note the shims I mentioned.


The floating type, this type usually has only one piston, the action of the piston moves or tilts the floating part on the other side of the disc thus pressing the brake pad onto the disc surface. The pic shows the shims, this one's off the barbie jeep, tricky little sod, it's got 12 shims in total on each calliper.

Re: The gear jammers thread

Found this link Harvey, hope it explains it.

http://en.wikipedia.org/wiki/Automatic_transmission