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Re: Front Dampers
Posted: Fri Jun 10, 2011 9:30 am
by Declan_Burns
klm wrote:Thanks Declan for your response and the information on the seal used on the rear damper. I note it is a single lip oil seal recommended for a push rod application. I have some questions.
Has this seal been successful in eliminating leaks through the shaft?
Are you presently using the overhauled damper?
Did you notice any score marks on the shaft where the original metal ring and rubber washers were in contact?
If the shaft was scored did you machine it to remove the score marks before fitting the seal?
Thanks
Yes the lip seal has proved quite successful-it's a lovely fit on the shaft but the outside diameter of the seal needs a few thou taken off the metal to prevent it splitting the housing. The repaired damper has been tested over the last few weeks on Hans Dieter's car and there are no signs of any leaks. There were no score marks on the shaft and there was no machining done just a straight replacement.
Regards
Declan
Re: Front Dampers
Posted: Fri Jun 10, 2011 1:49 pm
by bmcecosse
What oil are you running in it Declan??
Re: Front Dampers
Posted: Sat Jun 11, 2011 8:04 am
by klm
Thanks Declan for the response. I will first check if a suitable oil seal can be sourced locally here in Australia before ordering through eBay. Thanks again.
Regarding the rear springs, the original 7 leaf springs for saloons and convertibles have 7/32" thick leaves and they have the part number ACA5016Y stamped on the bottom leaf. The traveller springs have a different part number ACA5066 quoted in the Parts List and it is not clear what the differences are. The BMC Workshop Manual gives specification for the 7 leaf 7/32" thick rear springs in terms of a free camber and working camber. Does anyone know more about this subject?
Re: Front Dampers
Posted: Sat Jun 11, 2011 9:40 am
by Declan_Burns
bmcecosse wrote:What oil are you running in it Declan??
Roy,
The repaired damper is on Hans Dieter's car-I've passed on the question.
Regards
Declan
Re: Front Dampers
Posted: Sat Jun 11, 2011 1:38 pm
by Declan_Burns
It's SAE30.
Declan
Re: Front Dampers
Posted: Sat Jun 11, 2011 4:50 pm
by Declan_Burns
Here's a useful site as posted by Monacochris on another post and this seal should do
http://www.agrolager.de/product_info.ph ... d=31001588
Regards
Declan
Re: Front Dampers
Posted: Sat Jun 11, 2011 8:14 pm
by bmcecosse
Thanks Declan - and does it work well with that oil?
Re: Front Dampers
Posted: Mon Jun 13, 2011 10:21 am
by Declan_Burns
Seems fine.
Regards
Declan
Re: Front Dampers
Posted: Tue Jun 14, 2011 4:16 am
by klm
Hi Declan,
Did you use Fork Oil 30 or engine oil? Fork oil contains the same additives as hydraulic oil but if engine oil was used it is likely to breakdown after some time. Hydraulic oil is not available in SAE30 but Fork oil is, for use in motor cycles. It is a matter of peference on what viscosity of oil to use, and I found the movement of the arm to be smooth with SAE20 hydraulic oil compared to more viscous oil. Also the grade recommended by BMC was SAE20 which I guess the damping rate for the torsion bars and springs are set at.
Regards
klm
Re: Front Dampers
Posted: Tue Jun 14, 2011 5:24 am
by bmcecosse
Engine oil has even more additives than 'hydraulic' oil - it will last even longer! SAE 20 was the standard oil - the dampers work much better with 30, and better still with 40 ! I've only seen 'fork oil' in SAE 10 and 20 - but it may well be available in other grades in small cans - which could make it a more economic proposal.
Re: Front Dampers
Posted: Tue Jun 14, 2011 11:51 am
by Declan_Burns
Here's a close-up of the front damper seal showing the numbers but no manufacturer details.[frame]

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The numbers are 6948/5 and B29556 G 37
As the rubber is quite soft, it's difficult to measure accurately.
38.5mmm x 29mmx 7.4mm.
Regards
Declan
Re: Front Dampers
Posted: Wed Jun 15, 2011 10:35 pm
by mike.perry
KLM Ref spring types.
The original springs fitted to Series MMs to car 680463 were 7 leaf x 7/32 in. (5.56mm) These were replaced on the saloon and convertible by 5 leaf x 1/4 in. (6.35mm). The Traveller was fitted with 7 leaf by 1/4 in. Total spring thickness in mm = 38.92, 31.75 and 44.45.
It is a common mistake to fit the 7 leaf Traveller springs to Series MMs which results in less predictable handling, a harder ride and a jacked up rear end, particularly noticable with the high cut wheel arches.
Re: Front Dampers
Posted: Sat Jun 18, 2011 5:36 am
by klm
Thank you Mike for the information on springs. My car is a 1960 Convertible Chassis number 877700 series assembled in Cowley and it is fitted with 7 leaf springs. Were the cars for export continued to be fitted with 7 leaf springs while the UK cars had 5 leaf springs? It appears not much information is available on the specification of springs.
Re: Front Dampers
Posted: Sat Jun 18, 2011 4:34 pm
by mike.perry
Check if early 7 leaf or Traveller springs. Your car should have 5 leaf springs
Re: Front Dampers
Posted: Tue Jun 21, 2011 3:23 am
by klm
They are 7/32", 7 leaf. It is possible that the previous owner fitted 7 leaf springs for better handling.
Re: Front Dampers
Posted: Wed Jun 22, 2011 10:58 pm
by lockupchap
In last week's Classic Car Buyer Kim Henson recommends using proper hydraulic oil in dampers rather than engine oil, which he reckons can rot the dampers' seals. I hadn't heard this before - has anyone else? I'm topping mine up using up an old can of Duckhams Q found in a property I bought. The viscosity looks OK, it smells like only unused Duckhams Q did, but I wouldn't chance it in an engine due to its age.
Re: Front Dampers
Posted: Thu Jun 23, 2011 12:27 am
by bmcecosse
Hasn't rotted my seals in many years of use...........

The dampers are still fine too.