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Dubonnet suspension
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Chas Offline
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Post: #1
Dubonnet suspension
Anyone out there interested in Dubonnet front suspension repairs.
Applies to all models.

Regards.
Chas.

A pessimist sees difficulty in every opportunity. A optimist sees opportunity in every difficulty.
26/09/2013 08:37 PM
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Ian Till Offline
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Post: #2
RE: Dubonnet suspension
I'd probably be interested in some seals to sort my leaky ones out if you have identified any that will fit. My 1947 H is, I expect, the late type.
I haven't looked to see whether Chris's method for sealing the shafts is appropriate to the late H, but if I can replace the seals 'properly' that has to be worth a try first.
30/09/2013 07:04 PM
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Richard Offline
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Post: #3
RE: Dubonnet suspension
I would be interested in seals for my GY Wingham

Richard Hancock
02/11/2013 11:36 AM
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Chas Offline
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Post: #4
RE: Dubonnet suspension
Gentlemen,
The Dubonnet suspensions used by Vauxhall as everyone is aware, had a reputation for oil leaks via the carrier arm spinals.
Various sealing methods were used to combat the leaks in all models, but due to the make-up of the system and the non availability of certain materials they were always a problem.
In the past most of the Dubonnet suspensions were not maintained correctly, and were left to run as long as possible due to the cost of repairs.

The torsional tube/compensating types as fitted to the G,H,J,L model cars, when low on oil (even by 1/2 a pint), the top of the outer needle bearing would run dry. This bearing takes most of the suspension load as well as the shocks of carrier arm. Where-as the inner bearing did survive a little longer due to the load being at the bottom of the needle bearing.
Once the outer bearing starts to wear the inner suffers an alignment problem resulting in accelerated wear also (even if partially lubricated).

The same applies to the D models. These units are slightly different in as much they do not use a torsional tube system but rely solely on a internal load spring. The D sealing is a different kettle of fish entirely. Not having seal land on the spinal it relies on pressure contact of seal material between the housing and carrier arm.
See Chris Knapmans posts for a quick cure sealing idea. This does work as long as the bearings are not worn. It's a good idea to try it first before stripping the D units down.

With the exception of the D model, a modern double lip seal could be fitted.
But having said that I have yet to come across one that has been leaking, still being within tolerance and having a seal land for a lipped seal to work correctly. To fit a seal the unit would have to be completely stripped.

Repairs to the D type involve manufacturing new seal holder and spindle retaining arrangements, then machining to align the new needle bearing assemblies to housing.
Assembly involves careful assessment and adjustment of shims and spacers for bearing rings and rocker arm

Repairs to torsion/spring type require machining to align seal holder and new needle bearings. Assembly is the same as D type.

Consideration to all has to be made on assembling units, as no housings are dimensionally the same due to wear and tear over the years.

I am unaware of a seal size that will fit directly into the housings of the torsion/spring type suspensions at this time. The dimensions of seals are of course imperial and do not readily apply to the modern metric seals.

Regards.
Chas.

A pessimist sees difficulty in every opportunity. A optimist sees opportunity in every difficulty.
03/11/2013 10:26 PM
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Ian Till Offline
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Post: #5
RE: Dubonnet suspension
So... In a nutshell, if it is leaking, the outer bearings at least are probably shot and a new seal would be unlikely to work due to the shaft being in poor condition.

Does that summarise it?

But for the need to strip it down and expectation that the bearing is goosed, I would be inclined to look at turning up a carrier for a modern seal. Thinking about Chris's solution, I wonder if it would be possible to cut a modern camshaft seal to allow it to be pushed over the shaft and make a similar shaped carrier so that the top part only is open and the seal is retained around the lower 3/4 of the shaft.

Ian.
(This post was last modified: 04/11/2013 12:42 AM by Ian Till.)
04/11/2013 12:35 AM
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Chas Offline
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Post: #6
RE: Dubonnet suspension
(04/11/2013 12:35 AM)Ian Till Wrote:  Reply in blue.
So... In a nutshell, if it is leaking, the outer bearings at least are probably shot and a new seal would be unlikely to work due to the shaft being in poor condition. This is correct
Does that summarise it? Yes it does I'm afraid.
But for the need to strip it down and expectation that the bearing is goosed, I would be inclined to look at turning up a carrier for a modern seal. This would have to be attached (and sealed) to the housing) Thinking about Chris's solution, I wonder if it would be possible to cut a modern camshaft seal to allow it to be pushed over the shaft and make a similar shaped carrier so that the top part only is open and the seal is retained around the lower 3/4 of the shaft. Possible, depending on the amount of bearing/spindal wear and movement. I personally do not think it would last very long if it did work. Sorry.
Ian.

Regards.
Chas.

A pessimist sees difficulty in every opportunity. A optimist sees opportunity in every difficulty.
04/11/2013 08:03 PM
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neilyboy Offline
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Posts: 143
Joined: Dec 2013
Post: #7
RE: Dubonnet suspension
(04/11/2013 08:03 PM)Chas Wrote:  
(04/11/2013 12:35 AM)Ian Till Wrote:  Reply in blue.
So... In a nutshell, if it is leaking, the outer bearings at least are probably shot and a new seal would be unlikely to work due to the shaft being in poor condition. This is correct
Does that summarise it? Yes it does I'm afraid.
But for the need to strip it down and expectation that the bearing is goosed, I would be inclined to look at turning up a carrier for a modern seal. This would have to be attached (and sealed) to the housing) Thinking about Chris's solution, I wonder if it would be possible to cut a modern camshaft seal to allow it to be pushed over the shaft and make a similar shaped carrier so that the top part only is open and the seal is retained around the lower 3/4 of the shaft. Possible, depending on the amount of bearing/spindal wear and movement. I personally do not think it would last very long if it did work. Sorry.
Ian.

Just a thought on this but it could it be possible to metal spray the housing and shaft and have them turned down to suit modern seals bearings may be costly but would never have to be done again, any turners in our club for their views

neil
13/12/2013 08:46 AM
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