Discs and pads

[HumbleJim]

I'm getting some vibration through the steering wheel, medium braking from 70ish (worse after a long motorway run)
The pads have plenty of material on them the discs are down to 26.3mm (new 28 with a wear limit of 25.5mm and a service limit of 26mm)

Should I just bung some more discs and pads on or ask the garage to check them properly for run-out?

I don't really like asking the garage to check things that I will replace myself.

It's a Merc SL (1994) Pagid parts are around £130.
Should I always use a new fitting kit with pads? The old pads look like the wear sensor is built in so I guess I will need new sensors as well.

[james_gt3rs]

Disks and pads only cost £130? Probably worth doing if you have time/expertise.

[HumbleJim]

Older cars are often a lot cheaper.

[Toaster Pilot]

If the wear sensors are built into the pads, they'll come built into the new pads....

[mwstewart]

If your current parts check out OK start looking at suspension bushes and ball joints.

[InitialDave]

Perhaps have a look at the following:

http://www.stoptech.com/technical-support/technica...

http://www.stoptech.com/technical-support/technica...

However, as your discs are approaching the service limit anyway, I'd replace them as a matter of course. If nothing else, it's a lot nicer to work on cars in the middle of summer doing service work, than the middle of winter because you need to fix something.

[NateWM]

I would check the discs for "run out" first before I did anything else.

[HumbleJim]

Thanks chaps, I may get an expert to look before I just start randomly replacing things.

[HumbleJim]

Just looked at the rear discs again within tolerance but notice lines coming from the centre outwards on the disc. Is ths pads "picking up"

[lufbramatt]

Could be a sticky caliper causing the pads to drag+heat up, which leads to the deposits on the disc, causing the vibration, worth getting the calipers checked out first before the new discs get wrecked too. Just had this on my E39.

[HumbleJim]

lufbramatt said:

Could be a sticky caliper causing the pads to drag+heat up, which leads to the deposits on the disc, causing the vibration, worth getting the calipers checked out first before the new discs get wrecked too. Just had this on my E39.

Maybe the caliper feels fine no drag.

[lufbramatt]

HumbleJim said:

lufbramatt said:

Could be a sticky caliper causing the pads to drag+heat up, which leads to the deposits on the disc, causing the vibration, worth getting the calipers checked out first before the new discs get wrecked too. Just had this on my E39.

Maybe the caliper feels fine no drag.

Mine only did it when hot, felt fine jacked up on the drive.

[jay140285]

Got exactly the same as you but on a 2011 L200 Barbarian.

Going in for pads and discs tomorrow.

[HumbleJim]

I've ordered the rears from GSF.

[BritishRacinGrin]

As suggested, the caliper probably isn't working properly. Changing the discs and pads might help but if it does you have confirmed only that all you needed to do was remove and exercise the pistons, clean up the carriers and lube the pins. It's an expensive way to diagnose the problem.
On the other hand the calipers might be too far gone in which case the work won't solve the problem in the long term and you'll probably ruin another set of pads / discs finding out.

[steveo3002]

those marks on the disc look very much like where its been stood with the brake on for a while , not much you can do in normal use maybe leave the handbrake off if parked up for a while

[HumbleJim]

steveo3002 said:

those marks on the disc look very much like where its been stood with the brake on for a while , not much you can do in normal use maybe leave the handbrake off if parked up for a while

The handbrake is a drum with shoes.