Rear suspension squeaking

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fausto99
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Rear suspension squeaking

Postby fausto99 » 15 Jun 2020, 4:54pm

Calling any riders of 60s Moultons; is there a fix for the rear rubber block squeaking? Rather like MickF's rattly hub, it drives me nuts. I'm seriously thinking of replacing it with something else (if I ever finish the 101 jobs I already have on the go :oops:)

reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: Rear suspension squeaking

Postby reohn2 » 15 Jun 2020, 5:16pm

Squirt of GT85 now and again on the offending squeaky bit ?
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philvantwo
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Re: Rear suspension squeaking

Postby philvantwo » 15 Jun 2020, 5:41pm

Rotate it and fill it full of land rover grease!

Ugly
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Re: Rear suspension squeaking

Postby Ugly » 15 Jun 2020, 5:46pm

silicon spray does the trick

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fausto99
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Re: Rear suspension squeaking

Postby fausto99 » 15 Jun 2020, 5:53pm

philvantwo wrote:Rotate it and fill it full of land rover grease!

It is not hollow nor does it rotate. We are not talking half rubber ball of the AM and subsequent Moultons here.

I'm talking about the "real" (sorry MickF :lol: ) 60s Moulton with rectangular rubber block in compression/shear trapped between the main frame tube and the rear swing forks. If you've ever had a "real" mini (Austin or Morris) you'll know the cross between a squeak and a groan

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fausto99
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Re: Rear suspension squeaking

Postby fausto99 » 15 Jun 2020, 6:13pm

Ugly wrote:silicon spray does the trick


Thanks. Any particular brand?

Brucey
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Re: Rear suspension squeaking

Postby Brucey » 15 Jun 2020, 11:31pm

there are only three 'normal' causes of such noises in Series 1/2 machines

1) the pivot is unhappy in which case lube it

2) the rubber block is coming unbonded from its mounting.

3) the metal support is moving against the frame as the suspension is loaded.

IMHO under no circumstances should you lube the rubber block if it is coming away from its mountings; this will only hasten its demise, and make gluing it again more difficult than it should be. Getting glue into a noisy joint is a far better idea. If I knew of a suitable glue that works 100% of the time I'd say so. I plan to try UHU glue next time around.

However in addition do note that there are some abnormal reasons for noises too;

4) the swingarm is cracking (esp common in series 1 machines)

5) the main frame spar is cracking around the swingarm pivot.

Both the above can be fixed with lots of welding. The design isn't really strong enough to last for ever. I have repaired several bikes with 5) and I've reinforced the repair area so that a repeat failure is less likely.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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fausto99
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Re: Rear suspension squeaking

Postby fausto99 » 16 Jun 2020, 8:10am

Brucey wrote:IMHO under no circumstances should you lube the rubber block if it is coming away from its mountings; this will only hasten its demise, and make gluing it again more difficult than it should be. Getting glue into a noisy joint is a far better idea. If I knew of a suitable glue that works 100% of the time I'd say so. I plan to try UHU glue next time around.

Good point. Silicone is the enemy of adhesives and very difficult to remove.

I did have to re-attach the rubber to its mountings when I restored the bike BITD. I was working as a dev. engineer, in a loudspeaker factory at that time and they used a CA adhesive to glue rubber speaker surrounds to the metal chassis. It may have been Loctite 406. It was a low viscosity and black in colour because it had rubber particles suspended in it. It worked so well that the rubber surround would tear before the adhesive failed. Anyway, that's what I used to bond the rubber block to the mounting metal (The mountings are then pop riveted to the main tube and rear fork).

AFAIK UHU is a German brand name of various adhesives. The most commonly sold type in the UK is a solvent based, not very strong one. I would not consider it for rubber to metal.

The frame and forks was secondhand when I got it in the 80s. The rear forks were cracked and the rear pivot seized. I brazed the crack up myself and fitted oilite bushes in the pivot. I had access to oxy-acetylene then.There never been any hint of a problem at the rear, other than the noise.

Not sure what you meant by no.3. Which metal support? The one for the rear rack?

Brucey
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Re: Rear suspension squeaking

Postby Brucey » 16 Jun 2020, 9:28am

the metal support to which the rubber is bonded; if the pop rivets are not secure this could make a noise.

Interesting info about adhesives; Loctite 406 eh?

IIRC rubber to metal bonding has long been an issue in the automotive industry (bump stops etc) and adhesives that look as if they are going to work really well in lab tests have an annoying habit of developing new failure modes in the field. So adhesives that when lab tested cause failure in the rubber may fail between the metal and the adhesive layer in service.

FWIW I plan to try the UHU because I have not tried it before on this joint and although the adhesive isn't strong per se it is relatively tough so may be less prone to failure at the interface. It also cleans up with solvent, so if it doesn't work it won't be that difficult to remove it and try something else. Maybe. I recently repaired my cycling shoes with UHU (out of convenience rather than expectation that it would work really well) and to my surprise it is still holding up.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Ugly
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Re: Rear suspension squeaking

Postby Ugly » 16 Jun 2020, 9:53am

I have two cans of silicon spray, one is an expensive Thetford spray for their caravan toilets and the other is Halfords own brand , I can't tel the difference. This is splay lubricant not silicon sealant.

rmurphy195
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Re: Rear suspension squeaking

Postby rmurphy195 » 17 Jun 2020, 6:12pm

Ugly wrote:I have two cans of silicon spray, one is an expensive Thetford spray for their caravan toilets and the other is Halfords own brand , I can't tel the difference. This is splay lubricant not silicon sealant.


The Thetford spray, if its the one I'm thinking of, is for the seal on the cassette toilet, - it lubricates the black disc thing and the lips of the softer seal against which it moves.

The Halfords one (I too have both) feels quite different to me (much dryer), and works well on harder plastics _ I've fixed a long-standing issue with the seatbelts on my car with this by spraying it on the seatbelt guides. I wouldn't use the Thetford product for that it leaves a residue.

But I wouldn't use the Halfords product on the cassette toilet, in case it's missing something that the Thetford product has and might cause damage to the seals. Think about what's sloshing around in there while you're on the move, and where it might end up!
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !

mattsccm
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Re: Rear suspension squeaking

Postby mattsccm » 17 Jun 2020, 6:26pm

Mouse?

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Mick F
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Re: Rear suspension squeaking

Postby Mick F » 18 Jun 2020, 12:38pm

I had a Minivan for a few years back in the 70s.
Rear suspension rubber cones squeaked a great deal in the drier weather, and the only cure I found back then was to squirt WD40 at them every day or so.

Good old Sir Alec eh? :wink:
Mick F. Cornwall

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fausto99
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Re: Rear suspension squeaking

Postby fausto99 » 18 Jun 2020, 4:20pm

Mick F wrote:I had a Minivan for a few years back in the 70s.

Snap; a BMC green one, converted with side windows and a crude fold down seat. The front cones groaned on every bump in the road. Never did do anything about that.

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Mick F
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Re: Rear suspension squeaking

Postby Mick F » 18 Jun 2020, 4:31pm

Mine was Willow Green.
848cc.
Had a "chimney" on the roof and sliding windows.
Mini Mk2.
1968 model.
JTB 63F
Mick F. Cornwall