Front shock fluid

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Kilroy
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Front shock fluid

Post by Kilroy » Mon Jan 04, 2021 9:06 pm

Can anybody tell me the specifics of the shock absorber fluid please.
I wish to experiment with increasing the weight of the fluid to see if I can address internal wear in the mechanisms.
I can arrange motorcycle fork oil in 5W steps but imagine the original fluid might already be 10W ATF or similar.
Thanks.

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locost_bryan
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Re: Front shock fluid

Post by locost_bryan » Tue Jan 05, 2021 3:08 am

Bryan
Auckland NZ

1972 Morris Marina 1750 TC Coupe "Ozzy"
2008 Honda Jazz 1.3 CVT

Nothing gets the ladies hotter than software development analogies. Leonard Hofstadter - The Big Bang Theory.

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Kilroy
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Re: Front shock fluid

Post by Kilroy » Tue Jan 05, 2021 8:05 pm

Thanks Bryan.
Reading articles on both Minor, MGB and TR6 shocks, people are using up to 50W fluid to attain the level of damping they want, depending on the vehicles intended use.
I know from past experience that overdoing the valve adjustment can lead to cracked housings when the hydraulic pressure exceeds what the thin walled body can withstand, but the ability to increase the viscosity in steps of 5W should be a safe method of finding the sweet spot.

Like - I needed a project... ?? :wtf:

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Kilroy
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Re: Front shock fluid

Post by Kilroy » Tue Jan 05, 2021 8:07 pm

Oh.
Has anybody removed the arm from a Marina shock.?
It seems to be pinned to a spline, but I was led to believe it needs serious force to remove..?

Cheers.

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locost_bryan
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Re: Front shock fluid

Post by locost_bryan » Thu Jan 07, 2021 10:34 pm

Penrite have a 20W shocker oil for high performance or competition use https://www.classic-oils.net/Penrite-Shocker-Oil-2

One of the Minor forums suggested anything thicker than 30W will break the housing. Be interesting to see your test results.
Bryan
Auckland NZ

1972 Morris Marina 1750 TC Coupe "Ozzy"
2008 Honda Jazz 1.3 CVT

Nothing gets the ladies hotter than software development analogies. Leonard Hofstadter - The Big Bang Theory.

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Kilroy
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Re: Front shock fluid

Post by Kilroy » Fri Jan 08, 2021 11:16 am

Have flushed and refilled the first pair using Penrite SAE30 - designed for small engines.
Action feels firm but not dramatically more than with the original fluid which was in shocking condition - if you'll pardon the pun..

david painter
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Re: Front shock fluid

Post by david painter » Fri Jan 08, 2021 1:44 pm

I would suggest using Hydraulic oil as used in Tractors and Diggers, also used a lubricant in Aircon system s It has a anti foaming agent that mineral oil doesnt have, will also be kinder to the seals. Commonly in weights from 10 to 46 SAE
Dave

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Kilroy
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Re: Front shock fluid

Post by Kilroy » Sat Jan 09, 2021 8:10 am

Thanks Dave.
There are many factors to consider, but I decided to jump rather than slither, so took the plunge to simply see what happened.
I have enough spare shocks to consider some to be sacrificial, and the info I have absorbed reassures me that this has already been tried, so we will see.
Currently I have some doubts as to whether it is in fact the shocks that I am perceiving as the problem.
The estate had early front suspension fitted, and I converted it to Mk3 spec again, but I am wondering if any of the fitted parts may have incorrect dimensions.
I know the lower arms are correct as they had mounting points for the ASB, but I am not sure about the uprights which I simply fitted Mk3 swivel joints to.
I seem to have an issue where suspension deflection creates alignment issues, as would "bump steer", so I am wondering if I have an issue with steering rack length or some other factor which might indicate that some parts of my suspension are not all compatible.
I am now treating everything as being under suspicion, but I will fit a pair of "treated" shock absorbers to see what effect that has.
Empirical data speaks loudest.
Go well.
Kil

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locost_bryan
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Re: Front shock fluid

Post by locost_bryan » Sun Jan 10, 2021 10:32 pm

You removed all the Six suspension and steering bits that were originally fitted in the Coupe, and replaced with parts from your own Mk3 stocks?

The Six had a different bulkhead and transmission tunnel, with the steering rack mounted about 30mm higher. Worth checking that John Gobbe didn't source a rare Six Coupe shell, or raised the steering rack mounts to suit the Six suspension. Should be easy enough to compare to the estate, just to be sure.
Bryan
Auckland NZ

1972 Morris Marina 1750 TC Coupe "Ozzy"
2008 Honda Jazz 1.3 CVT

Nothing gets the ladies hotter than software development analogies. Leonard Hofstadter - The Big Bang Theory.

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Kilroy
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Re: Front shock fluid

Post by Kilroy » Wed Jan 13, 2021 6:23 am

I thought that this coupe shell may have been from a 6 due to the HD nature of the suspension and the fact it was equipped for twin trailing arms at the rear, but if what you say is correct, there is no way you could raise the steering rack 30mm in this shell...

Mk3 sedan.

mk3.jpg

Mk1 coupe.

coupe.jpg


The bracing structures dictate that steering rack must go in the usual location.
So that's nice.
Looks like I will get the Mk3 heater in there without too much trouble as well.
Have not started on the coupe project yet, as the estate still is not finished.

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locost_bryan
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Re: Front shock fluid

Post by locost_bryan » Wed Jan 13, 2021 9:21 pm

Your Coupe is definitely a UK Mk1 shell (YDO24 in Aussie speak), not an Aussie Six (YDO25) shell. The Six has a larger trans tunnel, and different bracing to the chassis legs. Photo courtesy of OzMarina.

Image
Bryan
Auckland NZ

1972 Morris Marina 1750 TC Coupe "Ozzy"
2008 Honda Jazz 1.3 CVT

Nothing gets the ladies hotter than software development analogies. Leonard Hofstadter - The Big Bang Theory.

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