Dave Jenner Posted December 6, 2012 Share Posted December 6, 2012 Hi all...I'm looking for any information I can get hold of regarding these Hydrovac Brake Servos that were made by Clayton Dewandre of Lincoln. I have one that will not work removed from an Alvis Salamander. It would develop a good vacuum, it had been bled through and I could hear and feel the piston moving within the power cylinder, despite this there was none of the normal 'feel' of any servo assistance at the brake pedal. Upon removal and stripping it down there was no obvious signs of any wear and tear; there seemed to be a rather excessive amount of oil in the power cylinder, but this was not as a result of a leak back through the push rod seal. In fact all seals seemed to be in good order with the exception of the cup seal in the hydraulic piston. Could the following be a reason for no servo assistance; if the cup washer/seal in the hydraulic piston was not working efficiently, could, when the engine is running and a vacuum produced, the power cylinder piston move forward under vacuum and push the hydraulic piston forward with no braking effect due to failure of the hydraulic piston seal? (if you get my drift). Anything on this would would be greatly appreciated, as always! Dave Quote Link to comment Share on other sites More sharing options...
Dave Jenner Posted December 6, 2012 Author Share Posted December 6, 2012 Reading this myself again, I realise that the power cylinder piston should not move, even with a faulty seal, unless air moves in behind the power cylinder piston to allow it to move forward ie when the brake pedal is applied. Back to square one! Quote Link to comment Share on other sites More sharing options...
roy meddings Posted August 25, 2020 Share Posted August 25, 2020 i have new ones in stock Quote Link to comment Share on other sites More sharing options...
Rootes75 Posted August 25, 2020 Share Posted August 25, 2020 Do you have other types aswell? Our 1950 Commer has a clayton dewandre type VH which we have been having troubles with. Quote Link to comment Share on other sites More sharing options...
andym Posted August 26, 2020 Share Posted August 26, 2020 I think that Alvis Stalwart owners might be interested too! Andy Figure G22.pdf Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted August 26, 2020 Share Posted August 26, 2020 23 minutes ago, andym said: I think that Alvis Stalwart owners might be interested too! Andy Figure G22.pdf 299.07 kB · 1 download The only thing to be aware of is that Stalwart brakes use Mineral oil in the hydraulics, whereas most commercial vehicles would be using conventional brake fluid. The seals would have to be suitable for mineral oil. 1 Quote Link to comment Share on other sites More sharing options...
andym Posted August 26, 2020 Share Posted August 26, 2020 2 hours ago, Richard Farrant said: The only thing to be aware of is that Stalwart brakes use Mineral oil in the hydraulics, whereas most commercial vehicles would be using conventional brake fluid. The seals would have to be suitable for mineral oil. Agreed! Quote Link to comment Share on other sites More sharing options...
Dave Jenner Posted August 26, 2020 Author Share Posted August 26, 2020 4 hours ago, andym said: Agreed! Hi Richard how you doing. I explained that also to the fellow that recently found and acquired his own Mk6...re the mineral oil. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted August 26, 2020 Share Posted August 26, 2020 1 hour ago, Dave Jenner said: Hi Richard how you doing. I explained that also to the fellow that recently found and acquired his own Mk6...re the mineral oil. Hi Dave, I'm good thanks, still firing on all cylinders! Are you still involved with Steve's museum collection? Quote Link to comment Share on other sites More sharing options...
Dore-Blanch Posted December 27, 2020 Share Posted December 27, 2020 On 8/25/2020 at 2:40 PM, roy meddings said: i have new ones in stock Hi there, I’d be interested in this. Having problems sourcing seals for the one on my Karrier gamecock Quote Link to comment Share on other sites More sharing options...
Harry Backhouse Posted January 5 Share Posted January 5 Hello, I have a Clayton Dewandre servo pump fitted to a Perkins engine, it is a rotary pump with 4 vanes which slide in the rotor to engage the cylinder, I am looking for 4 new vanes for this pump. I have searched the internet and cant find a similar unit, can anyone help please? Thanks. Harry Quote Link to comment Share on other sites More sharing options...
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