nick9one1
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| posted on 10/8/26 at 04:45 PM |
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MOT brake effort fail
Hi all,
First MOT in 13 years for my Stylus. it only failed on one thing;
Service brake efficiency less than 50% of the required value (1.2.2 (a) (ii))
Parking brake efficiency less than 50% of the required value (1.4.2 (a) (ii))
I had a chat with the tester and he said the car wasn't in the 'book' so they had to run it on the default values? - had a google about
this and it seems they can also run the test by using the 'presented weight' i.e. the rollers weigh the car and work out the brake force. I
asked him this and he said theirs cant do that as it doesn't have the load cells for vehicle weight.
The other thing he said is it's only the rears, fronts are fine. Which kind of makes sense because I completely rebuilt the fronts. He also said
without the weight selected it needs to lock up at least 3 brakes, and only the fronts locked up.
When I inspected the rear, it looked like they had been done recently. Loads of pad life and the retaining clips etc were clean. Even the pistons look
like they were replaced recently (albeit probably 13 years ago, just never driven).
I've ordered some new shoes, and will ask him to try again, but is he testing on the machine correctly?
(Escort mk2 rear axle, self adjusting)
thanks!
[Edited on 10/8/26 by nick9one1]
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jacko
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| posted on 10/8/26 at 06:31 PM |
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If this helps my mot station I used for the kit always used a de- accelerator
It was because it had a limit slip diff so no brake rollers
555
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perksy
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| posted on 10/8/26 at 07:11 PM |
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From Pistonheads :
"I own an MOT garage. As per DVSA instructions or our database we do not test LSD cars on the brake test rollers but use a de-accelerometre as we
don't want to damage a customers car. The car MOT pre test instructions advise u on this matter mostly! I would advise anyone with an LSD car to
advise the station before the test.
We get a lot of high end cars and classics for test because of the extra care we take and because we encourage owners to watch the test."
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JAG
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| posted on 11/8/26 at 07:16 AM |
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Does the OP have a limitied slip diff' on his car?
He doesn't say so in the original post 
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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Slimy38
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| posted on 11/8/26 at 07:35 AM |
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Just as an aside, I had far more trouble with braking efficiency with new pads than I do now, simply because it was challenging to bed them in. If you
do fit new shoes you might find the numbers get worse, not better.
For me I don't think this is an issue with your actual braking system, it's more that they're testing it against the wrong weight.
Either take your V5/IVA docs when you go for a retest (so they can use the correct weights) or find another MOT station.
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nick9one1
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| posted on 11/8/26 at 07:46 AM |
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thanks for the replies. I dont have an LSD.
But knowing this means I can test the handbrake at home. Google suggests that the MOT sees 1G of braking at 100% and 50% is required for a pass. For
the handbrake its 0.16G. Using my phone an d a g-meter app I can test before and after installing the new rear pads.
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scudderfish
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| posted on 11/8/26 at 08:57 AM |
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Here is the Ultimate Source Of Truth
https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/1-brakes
https://vetuner.co.uk
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russbost
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| posted on 11/8/26 at 10:43 AM |
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Fitting new shoes is likely to make things worse rather than better, as they'll then need to bed in. Did you check that both pistons on the
cylinders move freely & is the self adjuster taking up all free play, they frequently don't. Given the very light rear end of a 7 I'd
expect a very easy lock up on rollers. Does the handbrake hold on a steep slope & how is rear brakink controlled relative to front, is there a
pressure reduction valve or does it have dual master cylinders.
If a car they have no weights for failed I would have expected them to then do a decelerometer test, can you not request vthis or is that no longer a
thing, it's about 22 years since I last did MoTs!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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nick9one1
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| posted on 11/8/26 at 05:31 PM |
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Thanks all. I think I've sorted it.
as russbost suggested - I dont think the auto adjusters were fully adjusting. I manually pushed them out a click at a time until I couldn't get
the drum on, then went back one click. The handbrake holds much better now, and pulling it while driving can lock the wheels.
Also took a little time to scuff the inside of the drums with a drill flap wheel.
Booked in for a retest tomorrow
[Edited on 11/8/26 by nick9one1]
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jacko
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| posted on 11/8/26 at 05:42 PM |
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You could drive the car with the hand brake on a little to help bed the shoes in a bit
555
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nick9one1
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| posted on 12/8/26 at 09:31 AM |
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Passed with a clean sheet 
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adithorp
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| posted on 12/8/26 at 04:07 PM |
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Well done.
I'm a bit late to this party but I'll add a few tips (not all relevant in this case...
The angle of the slave cylinder means it can retain fluid above the bleed hole. Always bleed it with the adjusters fully off. If you still struggle
you can with the drum off, open the bleeder and manually push the higher piston back to expel and bubble hiding up there.
The auto adjusters will never fully adjust the shoes (whatever Ford claimed). At best they'll only prevent you loosing a pedal if the adjustment
is never done manually.
Adjusting manually should only be done with the cable let off so the lever is fully back against the shoe. If not you loose leverage.
Scribe a line on the adjuster agianst the cross bar (in this case) or down the shoe edge (in the case of vertical adjusters attached to the shoe) so
you can see where you started, if you go too far and have to let them off.
De-glazing the shoe and drum with emery or a light flap wheel can improve force if you're struggling... but don't go mad. New shoes will be
worst unless the old ones are knackered.
Once you've got them to the point you can just feel hear contact but not resistance, press the brake a few times and recheck... and again once
the wheel is on.
Only once your happy with that adjustment, adjust the handbrake cable. Double check they're free after.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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nick9one1
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| posted on 12/8/26 at 05:39 PM |
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thanks adithorp. Some great tips there! Even though it passed, I will rebleed and adjust using the method you suggest.
Always good to see a fellow Jeremy Philips kit car owner!
https://sscstylus.blogspot.com/
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scudderfish
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| posted on 12/8/26 at 06:33 PM |
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quote:
Originally posted by nick9one1
thanks adithorp. Some great tips there! Even though it passed, I will rebleed and adjust using the method you suggest.
Always good to see a fellow Jeremy Philips kit car owner!
https://sscstylus.blogspot.com/
Ooo, added to my feed reader
I occasionally post about my Fury at https://blog.smithfamily.org.uk
https://vetuner.co.uk
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