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Dewandre servo
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trampintransit



Joined: 09 Aug 2010
Posts: 166
Location: Edinburgh

PostPosted: Sat Jul 04, 2015 9:43 pm    Post subject: Dewandre servo Reply with quote

Anybody got any experience of Dewandre remote brake servos?..most particularly why does it need a reservoir whereas modern servos don't?
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Calum



Joined: 07 Feb 2011
Posts: 101
Location: Midgley, W Yorks

PostPosted: Sun Oct 04, 2015 10:39 pm    Post subject: Reply with quote

Only just seen this...

My Series IIa Land Rover is an early 6 cylinder model, and they received Clayton-Dewandre remote servos as standard from the factory (they were only fitted for a couple of years and then replaced with a pedal-mounted Girling thing, I think it was). There is no reservoir to store vacuum if that is what you mean? The Girling remote servo on the P4, however, does actually have a reservoir tank under the offside front wing
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goneps



Joined: 18 Jun 2013
Posts: 601
Location: Auckland, New Zealand

PostPosted: Sun Oct 04, 2015 11:48 pm    Post subject: Reply with quote

I'm open to correction here, but my understanding is that all vacuum-assisted systems will have an accumulator/reservoir. With the type fitted since about 1970 this is integral with the master cylinder, whereas earlier systems employed a remote brake booster, essentially just a separate reservoir.

Having no reservoir would mean that if the engine stalled there would be no pedal assistance, whereas a reservoir provides enough capacity to bring the vehicle to a standstill with normal assistance. Furthermore, the amount of assistance could vary, which could lead to some interesting control issues.

Richard
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jp928



Joined: 07 Jun 2016
Posts: 247
Location: Australia

PostPosted: Wed Jun 08, 2016 7:16 am    Post subject: Dewandre servo Reply with quote

All the vacuum servos I have seen or used have some reserve capacity without an extra tank. I have a VH44 on a clubman, and despite its small size it gives at least 3 applications after dead engine. To test this, run the engine, stop it (in a quiet place- garage), and apply the brakes - you should hear a moving air sound as atmosphere enters the booster to apply pressure; repeat until you can no longer hear the air noise - thats your reserve applications. Extra Vac tanks were fitted to upper class cars like Jag, Rover, Humber etc to give more peace of mind. Once you have run out of vacuum, the pedal will feel different, not going down as far, harder.

jp
26 Rover 9
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trampintransit



Joined: 09 Aug 2010
Posts: 166
Location: Edinburgh

PostPosted: Sun Feb 26, 2017 7:28 pm    Post subject: Reply with quote

Gave up on the Dewandre....took advise stating that it was a rubbish Sservo when it was new so why bother trying to restore it. I've now rtro fitted a girling type for a Rover P5
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billysugga



Joined: 01 Jan 2017
Posts: 55
Location: Carlisle

PostPosted: Sun Feb 26, 2017 8:16 pm    Post subject: Reply with quote

Some of the Clayton dewandre servos were similar to bendix hydrovac but I don't know if yours would be the same. I am having similar problems with a bendix one. Parts and information are tricky.
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