300TDi Fan Belt Tensioner

[RichardAllen]

I have just received a brand new Dayco fan belt tensioner mechanism from Paddocks for my 300TDi engine (part no ERR4708). It has not been fitted. I noticed it has a lot of play in the tensioner wheel bearing. This is difficult to describe, but if I try to rock it parallel to the axle (like you would testing a wheel bearing) I can easily move it 1/4mm + in either direction. If this were a wheel bearing I would definitely look to tighten it up a bit.

Is this play intentional, or have I a duff unit ?

Richard

[cipx2]

Check if the bolt that holds the wheel (bearing) to the body is tighten (LH thread) and if it goes in far enough to grip on the bearing inner race.

If all seems ok with the bolt, remove it and see where the play comes from: play in the bearing or between the bearing outer race and the wheel - either way is not good.

[RichardAllen]

Check if the bolt that holds the wheel (bearing) to the body is tighten (LH thread) and if it goes in far enough to grip on the bearing inner race.

If all seems ok with the bolt, remove it and see where the play comes from: play in the bearing or between the bearing outer race and the wheel - either way is not good.

Bolt won't shift and as it's brand new I don't want to put a breaker bar on it. It feels very wrong to have so much play, so back it goes tomorrow.

Thanks for the help

Richard

[rick]

It's a roller bearing so will have axial play.

A wheel bearing is a poor example to compare it to as they are taper rollers that have to be adjusted to virtually a pre-loaded state for correct operation.

A roller bearing like the type used in the tensioner has a single row of roller balls running in an inner and outer track and the spacing between the balls determined by a cage.

There is nothing to prevent some axial movement between the inner and outer races as they can rotate slightly in relation to the balls, and nor is it a fault as there will be some.

There is a fault if there is radial movement.

I have a Nachi book here somewhere that gives the ISO specs on these things but can't put my hands on it ATM.

[cipx2]

It's not a roller bearing, it is a ball bearing.

It does have an axial play though, but it's in the order of less than 10μm and this means you can't feel it by hand.

[RichardAllen]

It's not a roller bearing, it is a ball bearing.

It does have an axial play though, but it's in the order of less than 10μm and this means you can't feel it by hand.

Frankly, this wheel wobbles. It is not just sligthly feelable, my 2 tear old would notice it. Not good on a brand new OE part. I'll see what Paddocks say in the morning. Thanks for all the help.

[pat_pending]

[rick]

It's not a roller bearing, it is a ball bearing.

It does have an axial play though, but it's in the order of less than 10μm and this means you can't feel it by hand.

well all the new ones I pull out of the box must be cactus then as i can feel the axial play ??

And yes, you're right, it doesn't use rollers, I used the wrong term.

[PaulN]

Mine is an original and it wobbles too. Admittedly it is 13 years old but it does not seem to have any play or effect when under tension. I only know this as I have just got a new Serpentine belt and had the same thoughts when I had a a load of canaries under the bonnet after the new belt was fitted. (The old belt was cracked on the surface). Put the old belt back on and noise went. Spoke to supplier and turns out I had been sent one of 2 parts listed (both Dayco) so I returned same and go them to supply belt with same Dayco number as my noiseless old one. Waiting to try but will probably keep new one as spare.

My advice for any part such as this is to go to a M.Stealer and to physically look at it before you buy and make a comparison.

[Les Henson]

A brand new tensioner assembly should have no detectable play in it in any direction other than rotational (which should feel slightly stiff to turn). The bearing is fixed to the mounting plate, which is then bolted to the rear face of the timing case. Belt may be Dayco, but I didn't know they also made tensioners. I wouldn't fit it if I was you.

Les.

[rick]

A brand new tensioner assembly should have no detectable play in it in any direction other than rotational (which should feel slightly stiff to turn). The bearing is fixed to the mounting plate, which is then bolted to the rear face of the timing case. Belt may be Dayco, but I didn't know they also made tensioners. I wouldn't fit it if I was you.

Les.

Les, the water pump/fan belt tensioner is made by Dayco, they are the OE supplier. (The OE tming belt tensioner and idler bearings are made by Ina)

The Dayco pt. # is APV1004 for the 300Tdi fan/water pump belt tensioner and is quite a bit cheaper here than buying through a Land Rover supplier.

[Reiny]

Just send it back. I bought one from Paddocks recently (same part number and everything) and there's virtually no play in it. It works a treat.

[RichardAllen]

Just send it back. I bought one from Paddocks recently (same part number and everything) and there's virtually no play in it. It works a treat.

Thanks for that Reiny. Julian, the brilliant pasrts man at my local dealership in Cheltenham fished a Land Rove roriginal out for me and reckoned there was no noticeable play in it. I hope to take mine up to compare sometime this weekend. In the meantime paddcoks have offered a refund, but confirmed 'we sell 100's and they are all like that. Hopefully I can get it to my workshop, put a dial gauge on it and measure the 'runout'.

In the meantime, I have always found Les Henson's advice to be top notch, so the wobbly one is definitely not going into the vehicle.

[rick]

Just a FWIW, I pulled the spare used one out of it's box yesterday, the bearing had been changed approx. 20,000km before being retired (too much wear in the nylon bushing, the misalignment was causing belt squeaking) and measured the axial play with a dial indicator.

0.4mm movement at the periphery of the pulley.

[RichardAllen]

Just a FWIW, I pulled the spare used one out of it's box yesterday, the bearing had been changed approx. 20,000km before being retired (too much wear in the nylon bushing, the misalignment was causing belt squeaking) and measured the axial play with a dial indicator.

0.4mm movement at the periphery of the pulley.

Rick,

Thanks, measured by eye against a ruler the 'runout' was over 0.5mm. Unfortunately I needed to return it and did not get my dial gauge on to do an accurate reading. However, there is much less play in the old one, so I am going to try graphite lubrication on the new belt.

Regards

Richard

[rick]

Richard, it would be interesting to see what brand/country of manufacture bearing Dayco are now using.

I've seen a lot of Chinese bearings turn up in expensive genuine parts boxes (not Land Rover) from reputable manufacturers in the last twelve months or so for the various bits of gear I service.

[RichardAllen]

Richard, it would be interesting to see what brand/country of manufacture bearing Dayco are now using.

I've seen a lot of Chinese bearings turn up in expensive genuine parts boxes (not Land Rover) from reputable manufacturers in the last twelve months or so for the various bits of gear I service.

Rick,

Unfortunately I've sent it back now. I did briefly try to take thye wheel off to look at the bearing, but it was very tight, probably Loctited and I did not want to put it into the vice with a breaker bar, lnowing I was going to send it back anyway. I did woner if maybe they were using self-aligning bearings, but I looked on the SKF site, and this seemed to be more runout than you would expect from their standard range stuff. However, I am no bearing expert so may have missed something easily.

Regards

Richard