Failed MOT doh... Any ideas
Failed MOT doh... Any ideas
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quattrophenia

Original Poster:

1,103 posts

229 months

Monday 20th June 2011
quotequote all
Was told last year that the brakes will fail the MOT this year, so I put on new disks, pads, braided hoses and flushed it through with 2 litres of dot 5.1. The pedal is rock hard, the discs have done 2k miles now and are evenly warn-in and there is no shuddering or drifting under braking.
Car failed on 2 very trivial things which are sorted but also because of uneven braking force on the front wheels. The brakes are as good as they have ever been and having just spent several hundred pounds on new parts and considerable time on a refurb, I'm a bit pissed off to fail on that.
I intend to clean the discs with brake cleaner. Give the pads a light scuffing with a bit of sand paper just in case any oil/grease has got onto them and give the caliper pistons as good a clean and copper slip as possible.
Anyone got any other suggestions/remedies for the front brakes to be braking with different forces??
I didn't change the caliper seals as I'm not sure how so just cleaned them up cosmetically. Would a warn seal in 1 caliper cause this problem? Cant explain why it wouldn't pull to one side though?
I have 1 free re-test and 2 weeks to sort it.

M@H

11,298 posts

303 months

Monday 20th June 2011
quotequote all
It will be caliper related rather than disc related with the replacements as described. I would strip and clean both the calipers smile

gavgavgav

1,569 posts

260 months

Monday 20th June 2011
quotequote all
Free re-test, well done on finding a place that offers that anymore.

The post above does sound right, the calipers are quite sensitive to dirt and dust. Getting them to the point where you can move the pistons with your fingers freely is the key.

One extra point to add is that the caliper bolts were correctly torqued up and the calipers are not moving about (non-std calipers). This can cause one to drag a bit giving uneven braking.

As you've got new braided hoses and assume they are OK, check the copper lined for and crush points, not releasing can also cause uneven braking.

quattrophenia

Original Poster:

1,103 posts

229 months

Tuesday 21st June 2011
quotequote all
Well I spent a couple of hours cleaning and swapping bits over and the re-test was almost perfectly balanced fronts. cool
Now I have a green VOSA form instead of one of those hideous red ones, Yipee.
I am refusing to get my hands dirty for the rest of the summer now. Yeh right.