My fuel pump looked a mess......
Even though modern, reproduction fuel pumps are readily available, I was keen to try to retain my original and distinctive 'SEV-Marchal' pump. I had re-plated the top cover back in 2015, but have only just got to the point where I need to be refurbishing and refitting the fuel pump. Instructions for rebuilding can be found at Operation DX. 173-3, which can be found in section 2 of volume 2 of Citroen workshop manual 814.
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| Fuel Pump - 7 June 2015 |
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| Orientation of the Two Pump Valves |
Moving on to the bottom half of the body, the cam that operates the pump was released by carefully removing one of the tiny locking circlips from it's groove in the cams spindle. The cam was then unhooked from the base of the operating rod inside the lower body, allowing it to be pulled out - freeing the spring within. There were also two spacer washers that fit inside the body on the spindle.
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| Soldered Bolt on Diaphragm |
The bolt holding the diaphragm assembly together is locked with solder. I suspect that this is to set and maintain the correct operating force (pumping force) on the diaphragm spring. With this in mind, I marked the orientation of the bolt to the diaphragm before unsoldering it, and made a note of how many turns it took to separate the bolt from the operating rod. (Note: In Step 3 of Operation 173-3, the diaphragm and attached rod are removed as one - without removing the soldered bolt).
The small black rubber cup at the cam end of the operating rod was as hard as rock. In fact at first I wasn't even sure it was rubber. It was the workshop manual that confirmed it was. These parts aren't obtainable as spares and so it was make or break. I left the rod and cup soaking in a mixture of wintergreen oil and isopropanol alcohol for a couple of days*.
Wintergreen oil is the smell you get in Deep Heat. It is a very strong smell. People tend to either love it, or loath it. I left my parts soaking in the green house so that I didn't stink up the workshop! Personally I like it - but not in these quantities and strengths. I accidentally getting some of my mixture on my hands: the smell travelled everywhere with me. I poured some in a saucer. Despite washing it thoroughly first, dishwashing the saucer caused the whole dishwasher load to stink!
Miracle of miracles, after a couple of days the rubber cup began to soften with no signs of swelling. I left it a few more days but didn't want to push my luck. The pump diaphragm was showing signs of fatigue. Removing the metal plates that sandwich it, I gave it a bath in my wintergreen mix. Again, this had the effect of softening it.
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| Components of My SEV-Marchal Fuel Pump - 16 December 2017 |
With the valves removed and the rubber parts salvaged, the two halves of the body were taken away for vapour blasting - as was the metal spacer plate that fits between pump and engine. All the parts were then carefully cleaned before re-assembly.
The diaphragm sandwich was reassembled and the bolt tightened as per the note made during removal and then re-soldered. Reassembling the cam on the operating lever was fiddly because of the need to also align the spindle spacers in the body. I VERY carefully teased the circlip back on the end of the spindle and, after cleaning the end with alcohol, sealed it on with a small blob of Araldite. The valves were refitted - again using the copper water pipe reducer - and the body re-assembled.
Rather nervously I followed the instructions in step 12 of Operation DX.173-3 and tested the pump by emerging it in petrol and putting it under a little pressure to check for leaks. It passed muster. After draining, the spindle and cam were lightly lubricated with clean engine oil and I fitted the pump to the car. The smell of wintergreen oil dissipated (after about a week!).
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| Fuel Pump Fitted |
* CAUTION: there are different compounds of rubber and there is a danger that some may react badly to soaking in wintergreen oil and/ or alcohol. This may take the form of swelling (growing alarmingly in size) or the surface dissolving (black sludge rubbing off on your fingers). If you are tempted to try this but cannot afford to risk ruining a piece, then you would be better off finding another way.
I don't have Op DX 173 in my PDF 814 manual Vol 2 Section 2. I found the test procedure you describe in Vol 1 of the 814 PDF Op D173. I may attempt a partial strip down but would rather not desolder the nut. I've dismantled as far as separating the two main halves and had soaking in clean petrol for weeks,
ReplyDeleteHi Steve. Volume 1 covers 'adjustments' and includes checking the adjustment of the pump cam. The 'DX' operation added to some pdf copies of volume 2 covers pressure testing a fuel pump and is lifted from earlier manual 518. I think I realised (on reassembly) that you don't need to unsolder that nut/ bolt. I think you can remove it with the disc and rod.....
DeleteHi Paul. I spoke to Citroen Classics as I was trying to source a new gasket that fits under the lid of the pump and they advised changing all fuel pipes, hoses to omdern to cope with E10. They also said that the E10 would destroy the rubber diaphragm in this type of pump.Steve
DeleteHi Steve. Quite recently replaced the nylon fuel line to the tank. (see my post of 19 September 2022) and I bought a modern reproduction rubber elbow that connects it to the pump. Hopefully that is already ethanol resistant. There is then only a small amount of rubber hose to be replaced up to the carb. The diaphragm is more of a problem. Mine was weak and cracked anyway. Knowing it was on the way out, I managed to buy a modern reproduction a few years ago, so will keep that on standby. I bought it from Jochen Hoch (trading as 'CitroenDS') back in 2020. I have that on standby.
DeleteThanks Paul, I'll take another look.
ReplyDeleteHi Paul. I have been refitting parts to the engine including the fuel pump andinlet manifold. I haven't tightnened them up yet as I'm waiting for some new M7 nuts. I did as you have and overhauled my fuel pump which is the same type as yours. WhenI originally removed it the top half was rotated one screw clockwise - ie the top lid not at right angles to the block but at an angle. This meant that the suction tube was parallel to the block.(Hope that makes sense). After the overhaul I checked the orientation of the top half and saw how yours was here and is the same in the parts catalogue, so I changed the set up on mine when I reassembled. However on my dry run fit today it seems that the top steel vertical tube is almost touching the inlet manifold and little room for the hose to fit. I wondered if you had noticed that or had any difficulty. I concluded that the previous owner had rotated the top lid to give a greater clearance. I wonder if doing so would affect flow or performance?
ReplyDeleteHi. I can't see how the orientation would affect the pump at all. It's just a chamber. If you look at the last photo in my blog, I have clearance. The pump is in a fixed location so (as far as the original SEV pumps are concerned) the only other variable is the inlet manifold. Mine is a DS21 manifold. Other models have different carbs and different manifolds. A similar problem can occure with some fater market pumps. The manifold may be okay with a SEV pump, but the outlets on an after market pump may come out of the centre top of the pump - right under tha manifold.
ReplyDeleteThanks Paul. I thought the same with orientation. I think I will have to rotate as previous fit as the steel tube with the rubber hose is touching the manifold, which must be a non original or diff spec I guess.
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