tugboat Posted June 6, 2012 Share Posted June 6, 2012 As per a couple of my posts below, I bought a 1981 S3 109 2.25 Diesel SW earlier in the year for spares but found it to be too good to break. I've finally put a couple of days into it and one issue I knew I'd need to tackle before trying for an MOT is the lack of vacuum at the servo. It has the original throttle setup on the manifold but no signs of any linkage. Instead, bizarrely, it has a choke cable leading from the dash to a Heath Robinson mod around the throttle itself. I gathered from the PO that his predecessor had fitted this as a "starting aid". (Nuff said.) How it apparently passed several years of MOT tests like this is beyond me. The options I can see are: a) look out for some replacement linkages (likely to be a prolonged search); b) make up some mountings and fit a belt driven Peugeot vac pump, if I can find one (bit of a pain); or c) change the master cylinder for a non-servo unit. I'd prefer to do the latter - I've never had any issues with non-servo 109 brakes - but there seems never to have been a dual-line non-servo master cylinder option or I'd just buy one. Also, complicating things a bit, I gather that if the original standard setup was with a servo, then the fitment of non-servo brakes will result in a fail and so I need to know if the servo was an option or standard in the S3. I'm in a bit of a hurry otherwise I'd go for the vac pump option. All thoughts appreciated. Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted June 6, 2012 Share Posted June 6, 2012 The proper linkage was just an extra arm on the cross shaft with a rod to the butterfly lever and the fuel pump lever on the cross shaft had a lost motion action so that in use the butterfly opened before the injector pump. But that bit would be easily created as you should have a cable throttle so just set the cable with a bit of slack. The rod is an easy fix to make as any chandlers should be able to supply a pair of complete ball joints for 33c morse cables as used for throttle and gears on boats these days joined together by a length of 2BA studding. The extra lever is just the same as the one that the rod from the throttle pedal is connected to the cross shaft with. Quote Link to comment Share on other sites More sharing options...
Julian Posted June 6, 2012 Share Posted June 6, 2012 The options I can see are: a) look out for some replacement linkages (likely to be a prolonged search); b) make up some mountings and fit a belt driven Peugeot vac pump, if I can find one (bit of a pain); or c) change the master cylinder for a non-servo unit. All thoughts appreciated. Right, you can buy electric vacuum pumps especially designed for the job, for example guys using lumpy cams on V8's need them as they won't make enough vacuum at idle. probably much easier to fit than a Peugeot pump. My SWB series 3 diesel has been converted to single circuit non assisted MC by a previous owner, it stops fine, locking the wheels is easy enough. The genius who did the conversion took the pipe from the MC and fed it to a 3 way 'T'. The two outputs just go to the circuit failure sensing switch module. When I first saw it I laughed but then decided that it did the job well so left it. Julian. Quote Link to comment Share on other sites More sharing options...
tugboat Posted June 7, 2012 Author Share Posted June 7, 2012 Welcome advice, guys. I hadn't realised electric pumps were being used - nice easy fix, Julian. And sounds like the linkage issue is simpler than I'd imagined from read a other forum posts, thanks Phil. I've a spare bulkhead with some linkages attached, should be a crank or two on it. And I may actually have some 33c ends kicking around. The thread on the 33c is 3/16 UNF. I picked up some brass hydraulic connectors that size a few weeks ago which I've drilled and tapped one end to hitch 33c Morse cable to more easily sourced stainless M6 threaded rod (boat story). I'll have a look at my bits and pieces later today. Drawn to the electric pump in the longer term if I can't source one immediately - throttling a diesel is not too clever! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 7, 2012 Share Posted June 7, 2012 Electric vac pumps turn up used for cruise control on some stuff, I have one somewhere that came off a big Ford of 1990's vintage - if I had the first clue where it was I'd post it to you, but I'm busy moving house so the chances of finding it are about zero You could always swap the alternator for one with a vac pump on the back, probably find something that will bolt in with a bit of looking through here or some scrapyard rummaging. Quote Link to comment Share on other sites More sharing options...
tacr2man Posted June 7, 2012 Share Posted June 7, 2012 Disco cruise control 300tdi has a lecky vac pump IIRC Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted June 7, 2012 Share Posted June 7, 2012 ^^It does. It's a bosch unit, but I'm not sure it'd be up to pulling enough vacuum for brakes. You'd at least need an accumulator. Quote Link to comment Share on other sites More sharing options...
Snagger Posted June 7, 2012 Share Posted June 7, 2012 How's this for an alternative? Fit an electric fuel lift pump (easy and cheap enough to source from any scrappie) and replace the mechanical lift pump and mounting plate with a 300Tdi brake vacuum pump; the only issue is whether the cam shaft's lobe is of suitable profile, but I should think it'd work well if the other options don't work out. Quote Link to comment Share on other sites More sharing options...
Julian Posted June 8, 2012 Share Posted June 8, 2012 How's this for an alternative? Fit an electric fuel lift pump Or delete the lift pump altogether? The Lucas DPA does not need a lift pump, there's a generation of old Peugeots out there with the XUD engine that never had one - the DPA can suck fuel with its integral vane pump. I'd fit one of those in-line rubber hand operated priming pumps to assist after changing filters etc. Julian. Quote Link to comment Share on other sites More sharing options...
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