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XC90 '02'15 General Forum for the P2-platform XC90 model |
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MOT Failure - Foot brake 'efficiency'Views : 4976 Replies : 78Users Viewing This Thread : |
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Jun 29th, 2020, 13:45 | #61 | |
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New to this so I haven't had a chance to look at the shoes yet, I will take a look tonight and take some photos - what should I be looking for? Thank you |
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Jun 29th, 2020, 16:20 | #62 | |
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Regarding the shoes there should be about 4mm of lining thickness , but it should be obvious if they are thin . What happens is someone gets in and drives away with the brake on and wears them down . Easy to do especially if the grip is poor .. Another thing , any sign of rust on the drum surface is bad , the rust particles act like ball bearings so no grip .
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Jun 29th, 2020, 16:42 | #63 | |
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Okay yes that makes sense. Do I need to pull it out another click if the handbrake is fully on (holding the car at bite point) after 3 clicks on the foot pedal? Yes very possible that it could have happened back when it was barely holding it, will definitely check it out to make sure there's enough material left on the shoes. |
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Jun 29th, 2020, 16:45 | #64 | |
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Jul 4th, 2020, 13:23 | #65 |
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For those waiting on tenterhooks (not) I did finally get the car through its MOT through the week.
I changed the parking shoes for genuine Volvo ones, replaced the springs, disassembled the expander (which was fine) and re-greased it. Did the bedding in procedure, re-adjusted at both the console and in-shoe adjusters. Took it for its retest, an older chap stuck it on the rolling road, and pretty much came straight back saying "nope". He hadn't put it through the system, and gave me a chance to tweak the adjusters a bit more (I went prepared for that). Did some adjustments, a younger guy came out, took the car on the rolling road, and this time it was fine. He did say he really had to stamp on the footbrake, and suggested that the previous older guy perhaps hadn't pushed as hard, but given that I'd also adjusted things, who knows! I noticed that on the wall above the bay there were various numbers. After the first "nope" they were 70 and 90 on the left and right (with another number in the middle, but I didn't pay attention to that one), on the official retest the were both over 200, something like 220 and 250 perhaps. I'm presume they are some sort of measurement of force applied to get the wheels to move after applying the parking brake. Anyway, I'm obviously pleased, and I've backed off the adjustments a little, as drums were a bit hot after the drive home! I contacted the DLVA/MOT people about my reading of the MOT manual regarding testing the parking brake on automatic cars with P on the gearbox (particularly section 1.1.6), apparently it has been referred upwards, I'm still waiting a response. Just a comment on the foot pedal clicks thing. When mine just passed it took 8 or nine 9 clicks from the footpedal (I think 11 is the full travel). When I was looking at this at home, I had the armrest out so I could see the Y splitter. What I notice is that as I stamp on the peddle, to start with everything moves as you'd expect, but towards the end when I'm really applying some force to the peddle. The splitter barely moves, certainly not the amount it moves per click in the early part. My assumption then is that most of the "really stamping hard" clicks, are only resulting in stretching of the cable from the footpedal to the splitter. Neil For heck of it I've attached a couple of photos of the new shoe, in the drum and on the car. |
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Jul 6th, 2020, 15:47 | #66 | |
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also i thought parking brake was section 3.1 ?
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Jul 6th, 2020, 16:19 | #67 | |
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If the parking brake is the P position on the gearbox, the efficiency of the brake cannot be tested. The tester must therefore assess the brake by using a gradient (ideally 16%), or by attempting to push the machine when P is selected.In my email I did point out that the car has the foot operated brake as well. But if I want to park my car (and take the keys out of the ignition) I have to put the car in "P", so therefor to test the parking brake the gearbox needs to be in P. I asked if that's indeed the case. I also asked if section 1.3 doesn't apply as (like most modern cars) it has dual hydraulic brake circuits. - https://www.gov.uk/guidance/mot-insp...#section-1-3-1 And so section 1.4 does apply "Parking brake efficiency", but then see 1.1.6 on how to test on cars with a "P" gearbox. Neil PS That's a shortened version of what I posted here on the 18th https://www.volvoforums.org.uk/showp...8&postcount=35 Last edited by spiralarms; Jul 6th, 2020 at 16:27. |
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Jul 6th, 2020, 17:23 | #68 | |
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That is for quadricycles only :-) i was baffled it did not make sense .. Quadricycles may be fitted with one of the following types of parking brake: an over-centre lever that is mounted on handlebars a gear lever that operates a cable when its moved into the park position a transmission lock, which is the P position on machines with continuously variable transmission (CVT) These machines are type approved and should not be rejected for design features that prevent them from meeting the stated requirements. If the parking brake is the P position on the gearbox, the efficiency of the brake cannot be tested. The tester must therefore assess the brake by using a gradient (ideally 16%), or by attempting to push the machine when P is selected. The over-centre lever type can be brake tested as normal using one of the approved test methods.
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Jul 6th, 2020, 18:46 | #69 | |
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Just to keep the argument going though If section 1.4 is to test that the car holds securely while "parked", I don't see why the P position on the gearbox shouldn't be taken into consideration. Maybe I should save my frustration for when it next fails on the parking brake, or even be thankful if that's the only reason it fails! Neil |
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Jul 6th, 2020, 22:32 | #70 | |
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