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Clunk From Wiper Motor


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During testing of the motor i discovered a kind of clunking sound coming from the motor once every sweep.

At the same time this occurs you can also notice the motor give a little kick.

While the unit itself is of old 200tdi vintage, a few of the innards are new in order for me to run the old style motor in conjunction with td5 style wiper wheelboxes.

Any ideas what might be causing this? While the sweep/operation seems to be good, i couldnt put up with that noise knowing something isnt right...

Edit: i noticed there is a adjuster rod with a slotted end with a locknut on the motor. Whats this for?

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How much slack is there in the gear wheel and worm gear that the motor drives?

Mine has a bit of end float and clicks on each rotation. I think there is a screw on the end of the motor shaft to adjust it but it's been a while since I had mine apart.

For the sake of completeness it's worth asking the provenance of the replacement parts?

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Im not sure how much slack is in gearwheel/wormgear interface. Would i be right in assuming i would need to disconnect the spiral drive from the crank in order to check?

The parts i replaced when rebuilding motor was gearwheel/crank, parking switch and brushes if memory serves. Though whether or not they were genuine parts i cannot remember...

I may try tightening the screw a little to see if it makes any difference. I will update tomorrow.

Cheers

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From memory (and with my advanced years etc. etc .etc. :blush:) the motor has on the motor shaft a worm screw, this drives a gear that has a connecting rod onto the wipers, it sounds like one of the teeth on this gear has worn away, giving a "clunk" - the worm connects with roughly 2 teeth of this gear as in 1/2 the past tooth - 1complete tooth - 1/2 the following tooth.

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As mentioned in post above, the gearwheel is brand new.

In all honesty im a little perplexed as the things i thought would have worn ive renewed. Unless ive put it together incorrectly somehow though i dont think so as i rebuilt it exactly the same as it came apart.

As also mentioned above i will tighten adjustment screw a little and see if that helps.

One thing i did notice was that there is what appears to be a brass bush in the body of the motor. Has this been known to wear and make a noise?

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Are you sure its the motor and not the wheelboxes, td5 style sh@tpart wheelboxes are renowned for failing, could it be them causing the clunk?......

The clunk is coming from the motor as you can see it kicking. BUT what if the wheelboxes were making the spiral drive tight. Ie adding a bit of load to the motor?

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I'd be inclined to pop the cover off the motor, detach and pull/push the cable in its sleeve to see if theres much play in the wheelboxes.

All the motor does really is go round and round then the crank arrangement does the pushing and pulling, I bet there's play somwhere. How old are the wheelboxes and if recent were they Gen or Pattern. I fitted pattern to mine and anticpate the first time I flick the wiper when frosty (in error) they will fail...pattern ones have poor reputation....

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Disconnected the cable from the motor. Push/pulled cable to see how much resistance was in it. Im not sure how "freely" the cable should be through the wheelboxes. I was able to push/pull with hands but not as free as id expected tbh.

The wheelboxes are new (though not sure if genuine or not) so no play. Just not as free as id expect...

With regards the motor itself i was unable to turn the gearwheel by hand. Is this normal?

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No, you can't turn the gearwheel by hand the worm drive on the motor spindle will prevent that, did you notice if there was much of a delay between movement at the wiper when going from pull to push? I'm wondering if there is either slack or binding causing a delay that the motor catches up with causing the 'kick'?......

Does it look OK where the worm makes contact with the big gear?

Good luck!

Paul

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Hard to tell as i dont have the wipers on yet. Mainly to try and save unnecessary load on the battery as im not at engine running stage, therefore battery not getting charged.

Could be a little bind from wheelboxes as they dont feel that free. I have noticed the motor getting a little slower as if the battery is taking heavy load. Ok its not getting charged but its a brand new odessey pc1500.. I wouldnt have expected it to be struggling yet as ive only tested the motor half a dozen times or so?

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Is the dash all assembled? if not I'd be inclined to pull the wiper assembly apart and see if there's anything amiss. I dont think you need to remove the wheelboxes from the bulkhead, but if you could get the covers off the back of the wheelboxes, you could then try to see if a) The cable binds in the tubes or, b) the wheelboxes are binding or, c) its misassembled somehow.....or something is damaged...

I did the same a you I think to marry a tdi motor to td5 wheelboxes........it does work with no issues.....

The way the wipers work is pretty simple, (Im sure you realise this and am not trying to teach egg sucking), the motor turns the worm gear, which turns the big gear, which converts rotarty motion to push/pull......theres not really a lot to go wrong.......IMHO so,ething mist be either worn or binding or wrongly assembled, I just can't think what else it could be.......

The load on a battery from just a wiper motor with no drag from wipers, shouldn't quickly drain a good battery I dont think.....

Paul

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......The load on a battery from just a wiper motor with no drag from wipers, shouldn't quickly drain a good battery I dont think.....

Paul

IIRC the wiper motor is fed from a 10 amp fuse (so probably takes far less current than that), the PC1500 battery is a 68AH battery so at a really rough estimate you'd have to run it for 7 hours to have run the battery down.

caveat: there are lots of things I haven't taken into account but we're only doing a rough estimate here.

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Ok. So removed wiper motor from vehicle. With one hand i can push/pull cable through wheelboxes smoothly with no tight spots.

After stripping the motor for an inspection to see if id assembled something incorrectly i did notice something. There seems to be a bit of play between the gearwheel (which is new) and the brass bush it locates into. In fact i could almost replicate the noise it makes once every revolution by grabbing the gearwheel and moving it within the bush.

Everything else seems fine.

Im beginning to think replacement motor is needed as the bush isnt a part you can buy separately.

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  • 2 weeks later...

Just discovered something very interesting... Well maybe not.

As above when I tested my new wiper motor out, the clunk had gone. Sorted i thought. Think again....

As soon as i fitted my 140 tooth gearwheel into the motor and retested....guess what......CLUNK! Grrrrrrrr!

So i reckon that the gearwheel is maybe cheapo and decide to purchase a new genuine LR item. Shiny new gearwheel arrived today and i hurredly fitted it thinking i could finally put this to bed and get on with building rest of the dash.... Nope. CLUNK!

Im stuffed. The only think i can think of is that the shaft of the 140 tooth gearwheel is very slightly smaller than the shaft of the old type 200tdi gearwheel. They must be made by a different company. The td5 (140) gearwheel is black whereas the 200tdi gearwheel is white.

So im now in a position where if i refit the original gearwheel the wiper sweep will be wrong.

Any thoughts other than put up with the clunk (which would do my head in) or buy a td5 wiper motor (which i think then means i cant fit my old 200tdi dash)

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Mine is a 1993 2.5 petrol 90 (yes a very late petrol 90) anyroad up, I rebuilt it as a 300tdi on new chassis and td5 bulkhead, which meant using td5 wiper boxes, I fitted the different wheel into the original motor with no issues and the sweep is correct with no clunking, I also used a Genuine part gear wheel. Not sure what's going on with yours, it should be a straight swap........can you try a different motor?

Paul

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Hi Paul,

The motor im using is a brand spanking Lucas one. I replaced the original thinking that it was the cause of the clunk as the 140 gearwheel seemed to be a loose fit in the brass bush in the body of the motor.

What i have noticed is that the original gearwheel is a nice tight-ish fit in this bush, whereas the 140 gearwheel just slides in and out.

Edit: Maybe im being too picky and i wont hear it when engine running etc, but there is definately a difference between the gears as when i had the original 200tdi style one in, it was near silent.

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Afraid so Ralph :(

Ive now tried 2 different 140 gears in 2 different motors, and always get the same thing.

I think there must be some difference between the 200tdi gear/bush interface, and the td5 gear/bush interface. The td5 gear seems to be a tiny bit smaller than the 200tdi gear.

Like i say maybe im being picky, but there definately is a slight clunk when using that combo of motor/gear.

Maybe i should do what Simonr did in a 2012 thread i just read whereby he fitted old style 300tdi wheelboxes into his td5 bulkhead. This would let me use the original gear.

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