MOT Brake Question

S

speed12

Member
Hi, I should know this but thought I would seek clarification.

My Coupe is due an MOT in the next month, during the MOT do they merely test the brake efficiency/ performance or do they also check the brake pad thickness too? also I have warped front discs (annoying but I'm putting up with it until I get round to changing discs and pads all round), will they fail a car for having warped discs?

Ideally I would like to change the brakes before the MOT however this weekend is out due to a stag do, next two weekends after that are out dur to Holiday.

One final question regarding MTEC discs which I am considering, I notice that they now come with coatings, whilst the coating is a waste of time on the friction surface does the covering extend to the visible hub area which typically corrodes on standard pads?

Regards
 
Yes they will check pad thickness and can fail it if badly worn
Warped discs can also fail as it shows up on the brake tester
 
Hmmm guess I better get some discs and pads ordered then.

PS Andy - I notice you live in Stone, Im just up the road from you in Fulford. Small world.
 
Mot can't fail you for pad thickness ... That's why there are sensors on the pads . Providing they are working they won't bother you if they wafer thin it will be advisory . If it's a small warp it won't show on the rollers and if the imbalance is below 30%youll get away wih it . As for the mtec yea coat scrubs of the braking area and leave a rust free looking disc
 
"One final question regarding MTEC discs which I am considering, I notice that they now come with coatings, whilst the coating is a waste of time on the friction surface does the covering extend to the visible hub area which typically corrodes on standard pads?"
**********
Yes..... keeps the hubs an disc edges tidier looking longer
 
Brake pad thickness, or lack of it, can most certainly result in MOT failure. Here is an excerpt from the .gov website.

•Excessively worn pads/shoes can often result in an MOT failure. Brake pads and shoes are designed to wear through time due to use. The lining component will wear when it rubs against the brake disk or brake shoe. When the lining wears down it is possible for contact to occur between the metal of the pad and the disk. When this happens the disk will become scored. A scored disk will reduce the braking efficiency on the effected brake unit. You should regularly inspect your brake pads and shoes, or have them inspected for you by a competent mechanic. If components are worn they should be replaced.

I was unaware that the rollers could show a warped disc so perhaps andy6409 could explain how it does that.
 
When I purchased my car the seller told me the pads were thin as he'd had an advisory on the last MOT of his ownership, fast forward to the first MOT I have with this car plus the 5k miles since the previous MOT & the brakes never got mentioned. :roll:

In fact, after the MOT I got chatting to the guy as I said I intended to fit new discs & pads soon & he did agree that the pads had nearly had it (more so the fronts) but he said there was "plenty of meat" left on the discs, so last weekend I took advantage of ECP's bank holiday discount & just replaced the whole set of pads only.

I reckon you could do your disc's & pads in a couple of hours, as long as you've got a G clamp to push back the piston in the caliper & some method of drawing up some brake fluid from the reservoir you'll be fine. (I used a turkey baster for this :rofl: )
 
Brake warp shows up on the brake tester as the pressure on the disc at the warp drops off over the area of pad. The machine detects this pressure drop. On older analogue testers you can physically see this as the pressure indicator needles on the machine flutter rather than remaining steady. On digital ones the numbers fluctuate or the machine will average out this flutter as a reading.

Cant hide warped discs on either machine. As a previous post states 30% max. On a previous bike I had 20% on the fronts which was just an irritating vibration on braking, more a feeling of the brakes pressure varying over the disc, could feel this on the bike.

On the car it will be a minor vibration or brake pedal pulse. Any significant vibration under braking will be more than 30%
 
I've just replaced mine all round in readiness for a mid June ring trip , mtec grooved discs and red pads , I don't try that hard these days :D
If your replacing the discs as well you don't even need a g clamp , just lever the pistons back in with a screwdriver between the pad and disc , they are scrap anyway . 3 hours tops working on the drive .
The disc and pad combo seems to work well considering how cheap it is .
Paul
 
Denis O said:
Brake pad thickness, or lack of it, can most certainly result in MOT failure. Here is an excerpt from the .gov website.

•Excessively worn pads/shoes can often result in an MOT failure. Brake pads and shoes are designed to wear through time due to use. The lining component will wear when it rubs against the brake disk or brake shoe. When the lining wears down it is possible for contact to occur between the metal of the pad and the disk. When this happens the disk will become scored. A scored disk will reduce the braking efficiency on the effected brake unit. You should regularly inspect your brake pads and shoes, or have them inspected for you by a competent mechanic. If components are worn they should be replaced.

I was unaware that the rollers could show a warped disc so perhaps andy6409 could explain how it does that.
Click to expand...


This means what it says , if they on the metal you will fail .... A pad with a sensor fitted will put light on in dash and then fail lol so I'll go back to what I said if there are sensors fitted and the pad is thin with no warning light on it will pass .... I have the pleasure of doing at least half a dozen a week :wink: .........
 
Thanks for the replies.

I've ordered mtec grooved discs with silver coating and minted pads just over £200 for the set of front and rear. I'm intending to do it myself and paint the callipers too. Cant decide whether to use some existing hammerite black paint or go silver.
 
speed12 said:
Thanks for the replies.

I've ordered mtec grooved discs with silver coating and minted pads just over £200 for the set of front and rear. I'm intending to do it myself and paint the callipers too. Cant decide whether to use some existing hammerite black paint or go silver.
Click to expand...

Re the colour, does the below thread help?, I did mine silver using Hammerite smooth, initially I was disappointed, however having got the car in daylight the calipers just look as if they were new, my pic doesn't do the silver caliper justice IMHO.

http://www.z4-forum.com/forum/viewtopic.php?f=49&t=65053&p=961268&hilit=caliper+paint#p961268
 
TonyP said:
speed12 said:
Thanks for the replies.

I've ordered mtec grooved discs with silver coating and minted pads just over £200 for the set of front and rear. I'm intending to do it myself and paint the callipers too. Cant decide whether to use some existing hammerite black paint or go silver.
Click to expand...

Re the colour, does the below thread help?, I did mine silver using Hammerite smooth, initially I was disappointed, however having got the car in daylight the calipers just look as if they were new, my pic doesn't do the silver caliper justice IMHO.

http://www.z4-forum.com/forum/viewtopic.php?f=49&t=65053&p=961268&hilit=caliper+paint#p961268
Click to expand...

Thanks, Silver looks smart and might look best against my 108's which have been powder coated to a dark gun metal grey. I did Think red initially as my coupe is blue, but I dont want them too look too obvious.
 
One quick question on the topic of changing pads and discs

Is the procedure any different for the rears? I was unsure what implications the handbrake has?
 
I wondered this too but had no issues when I did the rears, the piston just pushed back in much the same as the fronts.

If I'm honest, I don't know how the handbrake works as I don't recall seeing any handbrake cables, does it work on the propshaft?
 
Roundozo said:
If the handbrake is the same as the E46 then its inside the rear disk hub.
Click to expand...

Ok, I'm sure the handbrake cables are there then, just don't recall seeing them :roll:
 
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