Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
WELL NOW, THIS "IS" A NEW ONE!
Like many on here I've replaced more of these than I'd care to remember, and I've seen my share of broken belts too.....
But, I have not seen a new HPFP belt fail after just 9,000 kms until now
Click image to enlarge
The belt kit was DAYCO (2018) and was fitted together with a new tensioner, the direction mirroring that of the front. At this point I can see no obvious reason for the failure, but I am open to suspicions regarding the integrity of HPFP or elsewhere. Though it does appear to be fine and turns normally, cam pulley is also fine, as is the casing, and as you would expect the tensioner is "as new"
I have only ever used DAYCO belts for both LR and some other manufacturers with never the slightest issue in what must be 30 years using them. This leaves me slightly suspicious there may be something else going on which is not immediately obvious.
Of course it's possible the belt was just faulty, though the fact that it was a 2018 manufactured belt shouldn't have any impact as it is still now within its time based lifespan. I'm now beginning to wonder about the front belt, though that was a 2019 belt when fitted.
If the belt was not faulty, it would take phenomenal force to break it such as it is. The question is what?yµ (idµ - eAµ) ψ=mψ
3rd Aug 2021 3:46 pm
rrhool
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4400
I've thought this many times. What if you change a timing belt (or other) because it's due by time or miles, and the one you fit was manufactured incorrectly?!
The process control on the manufacture of automotive components should result in nearly no defects, but no process can be 100%.Richard
D3 SE 2007. Triumph 2.5Pi 1973. Ferguson TEA20 1948.
Discovery 2 4.0 ES 2001- Gone
Discovery 1 300Tdi ES '95 - Gone
Range Rover Classic '79 - Gone
3rd Aug 2021 4:19 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Well yes, I agree regarding manufacture process and to be fair I have never had a failed belt in over 40 years of fitting them.
Perhaps I'm over analysing it and I should be grateful it wasn't the front belt
I never liked belts and always preferred the chain set up. Though they do fail too
I'm just nagged there might be something else going on that I'm missing.yµ (idµ - eAµ) ψ=mψ
looks like all the threads failed at same point so I'd say something catastrophic happened to the belt across it's width.
could something have got "into" the belt then when it went over a pulley, it just cut it enough to break a number of threads ?.
Dean
====================================
2011 D4 XS - OBD port protection, RLD spare wheel protector, All LED interiors lights, Timed Climate enabled, iiD tool paired.
2011 D4 Landmark - Stolen from same dealer before I paid for it
2011 D4 GS - Stolen whilst at dealer ... All LED interiors lights, DRLs, Spare Wheel protector.
1996 300Tdi - Eaten by tin worms
3rd Aug 2021 4:58 pm
Dimcandle
Member Since: 06 Feb 2020
Location: North Wales
Posts: 195
I've seen this happen once, the belt was nipped on one edge when installed, let go a few thousand miles later
3rd Aug 2021 5:00 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Hardware wrote:
looks like all the threads failed at same point so I'd say something catastrophic happened to the belt across it's width.
could something have got "into" the belt then when it went over a pulley, it just cut it enough to break a number of threads ?
There's nothing in there now Dean if that was the case. It does look like massive force ripped it apart which is what is puzzling me.yµ (idµ - eAµ) ψ=mψ
3rd Aug 2021 5:09 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Dimcandle wrote:
I've seen this happen once, the belt was nipped on one edge when installed, let go a few thousand miles later
It was fitted with the body off which makes for a very simple and unobstructed install. I always count the teeth just to be sure its the correct 82 late/85 early. I would have thought I'd have spotted any damage.
Of course it is still possible I missed something, but look at this:
Click image to enlarge
To my eyes this looks like either the belt failed, or something placed massive force on it to rip it apart.
There's not even a scintilla of wear or any inkling of something untoward, just what looks to be brute force.yµ (idµ - eAµ) ψ=mψ
3rd Aug 2021 5:24 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
Does the HPFP turn ok? Its possible that something has jammed the pump.
It may also pay to conract Dayco they may be able to test the failed belt.Andrew
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
3rd Aug 2021 6:47 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Yes it turns fine Andrew but I remain suspicious. I've never known HPFP to lock up but it's design is not too dissimilar to an engine.
And we all know what they can get up to. yµ (idµ - eAµ) ψ=mψ
3rd Aug 2021 6:59 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8109
If it’s manufacture failure there will be a others of the same batch that will fail, AFAIK the manufacturing process produces a wide belt possibly 2mtr wide and then single belts are cut off, if one has failed the whole batch may fail. Are you sure nobody’s missing a spanner? It can when others can't,
It will when others won't,
It goes where others don't.
3rd Aug 2021 7:08 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Yes, now that you mention it I'm missing an 18 mm combo, but if that was in there she'd have spat the cam pulley and the pump drive gear through the bonnet.
Nice try though yµ (idµ - eAµ) ψ=mψ
3rd Aug 2021 7:13 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20732
I've had an identical failure a while back, also HPFP belt, and an EU4 engine
Belts and oil pump replaced, some time later, car recovered in as non start
No HP pressure when cranking, so checked back belt, and was exactly the same as pictured. Clean failure, pulley moved fine, HPFP moved fine, new belt kit fitted, and it's been fine ever since...My D3 Build Thread
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8109
:thumbsup:By coincidence I have been working on a Kubota engined mower today, the alternator belt was slipping to the degree the engine had to be emergency stopped, on examination the alternator had locked solid caused by dust in a small internal bearing in the alternator, irrelevant I know but could lt be a clue to you problem?- toothed belts can’t slip something has to give.It can when others can't,
It will when others won't,
It goes where others don't.
3rd Aug 2021 7:30 pm
motorworks
Member Since: 14 Nov 2019
Location: Usk
Posts: 401
If you look at the second picture, it seems that the belt was expanding on the right side. Also, in third picture there appear to be signs of bubbling above the break. I think a section of the belt was failing, and the break point was the weakest/worst.
I know nothing about belt construction, but I would expect a common cause of failure to be internal friction. Polyester fibres are very strong, until they reach critical temperature then they break.Chris
3rd Aug 2021 7:31 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Disco_Mikey wrote:
I've had an identical failure a while back, also HPFP belt, and an EU4 engine
Belts and oil pump replaced, some time later, car recovered in as non start
No HP pressure when cranking, so checked back belt, and was exactly the same as pictured. Clean failure, pulley moved fine, HPFP moved fine, new belt kit fitted, and it's been fine ever since...
That's exactly how this played out too.
Car came in this after lunch as a non starter. No fuel pressure on cranking so went to the rear belt and the rest you know.
Is that the first time you have seen a relatively new drive belt fail Mike?
It is for me.
Every day is a school day I suppose. yµ (idµ - eAµ) ψ=mψ
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... All LED interiors lights, DRLs, Spare Wheel protector.
