The Lucas CAV DPA diesel injection pump on my CASE 580se was a leaking mess and the engine was no longer starting. After watching all the videos on YouTube of the procedure, I bought the required new parts and ran thru the procedure myself. Although time consuming to do this the first tiime, the result was very successful, the leaks are gone and the engine starts immediately, like it never did before. The pump was extremely dirty outside and inside and it took a lot of time to go thru the procedure carefully disassembling, making notes with pictures and cleaning the parts which were covered in 35 years of accumulated sludge. I did not remove the transfer pump rotor from the ‘hydraulic head’, that’s the piece the vanes sit in. I did remove the pump plungers and carefully cleaned them and their ports until they slid freely back and forth. In my case, the accumulation of fuel deposits was interfering with plunger movement. Once the plungers were clean and manually primed with a bit of fuel forced in with a syringe, I could actually feel the plungers pressing outward against my fingers. Or if I held one plunger in while priming with an oil filled syringe, I could then push in one side and the opposite plunger would be pushed out. The combined amount of plunger movement is probably less than ¼” but was now unrestricted. Once the rebuild was completed, for bench testing the pump I devised a small , 1 cup, fuel reservoir to feed the pump and used a cordless drill with a socket to spin the pump. With this I could then see the injection pump shooting a bit of fuel 2-3 feet straight out each banjo pipe as the pump turned. After this I felt confident the pump was working correctly. My lessons learned , things I should have done better from the start: - First, watch all the videos and read all the documents - make careful notes and take lots of pictures that show the order and position of each part as it is removed, time spent on this will definitely save time later - the position and order of each part is critical and no I wont remember - a soft wire wheel works well for removing crud from non-precision fit parts - Alcohol works ok as a cleaner/solvent - Final clean is a dip in solvent followed by blow drying with compressed air to remove any bits of dirt or cloth fibers - New ZipLock baggies are good clean containers to hold and organize the parts as they come off and are cleaned . - Use the torque specs for reassembly, some fasteners are delicate and some need more than I thought in order to not leak fuel - Some witness marks are helpful for final alignment - Important: A method for bench testing the pump so you can see it shooting out the diesel fuel 2-3’ from each line BEFORE re-installing the pump is mandatory to remove ANY doubt about the success or failure of the rebuild - Complete bleeding of the fuel system after pump re-installation is mandatory to remove any and all air, starting with removal/filling both fuel filters, thru all fuel bleeders, high pressure fittings at pump and ending at injectors. - If fuel isn’t ‘spitting’ but only seeping from cracked-open high pressure fitting, something is wrong , air still in lines, it will never start, redo bleeding . - No smoke from exhaust? Something is wrong, it will never start, don’t bother with starting fluid, redo bleeding. Parts I used: - CAV injector pump rebuild kit 7135-70/7135-110 , SPACO made in Italy $24 - Two oil seals for the drive axle are not included in the above kits so had to be ordered separately ( CAV Lucas 5393-252R DPA injection pump drive seals) $11/ea - A second large triangle gasket is required, the kit only includes one. - Pump blades/vanes $11 Manuals and documents, these include functional descriptions, disassembly steps, torque values etc: https://injectionpumps.co.uk/cav-dpa-manuals/ or https://www.fujiyachts.net/manuals/CAV DPA Pump Rebuild Manual.pdf Interactive parts diagram https://injectionpumps.co.uk/interactive/interactive-cav-dpa-parts-diagram.htm
If u didn’t remove the transfer pump rotor, that means u removed the 2-5/16” screws on top of the rotor.. THATS your max fuel setting.. You should NEVER TOUCH THOSE SCREWS.!!! Live and learn I guess.. it sounds as if your main problem was stuck plungers and u managed to free them up.. Way to go..
I agree, way to go. I admire your courage. It is hard to argue with success. I actually refuse to try to repair injector pumps. I send them off to my pump guru on the next island. When a client asks me, "can't you just replace the gasket on that cover?". The thing that goes through my mind is that almost last scene in raiders of the ark when the Nazi's open the ark on the island. I don't know what is under that cover and I don't want my face to melt off when some ungodly crap comes flying out of it.
I was careful to make witness marks so I could reassemble it back exactly as it was. It’s interesting to note that the pump is designed so that the max fuel setting can be changed thru the side port without removing the pump from host machine. It’s really a fantastic piece of mechanical design and engineering, simple yet effective. Witness marks to aid precise reassembly Testing plunger movement by forcing oil thru port with syringe feeling the free movement of plungers under pressure from syringe priming
Your 1st statement about changing the max fuel on the machine is false.. It’s made to b changed on the test stand where u can monitor the change in delivery.. NOT on the machine.. The slightest change in movement of the fuel plate, makes for A HUGE difference in fuel delivery.!!
Correct, I should have said “without dismantling/disassembling the pump”, but the point is that these mechanical CAV DPA pumps are an engineering marvel.
Yes, yes they are.. What I find amazing is, they’ll run + or - a bucket of dirt.!! Try THAT w a Stanadyne pump.. How many times has someone pulled the top cover off a CAV DPA to find it FULL of mud and water, yet still running, and only leaks.?!! Unlike the Stanadyne/RoosaMaster pump who built in a problem to MAKE YOU pull it off to b repaired every few years.. (flex ring) Oh, and let’s not forget about their price hike this year.!!! Stanadyne parts jumped 65% in February/March .!! I kept my prices the same until I ran out.. Then, had to bump them up “slightly”.. (I’m still 200. cheaper than the big shots)
You did good to reseal that pump. I have the same on my 580e. I’m wondering if you might know why my engine won’t start after it’s warmed up. I’ve replaced the fuel shut off solenoid. I also connected a good battery right to the shut off solenoid to open it. It won’t open because of pressure on that side of the pump. It will start if i open the valve on the fuel filter and blend off a little fuel.
The only thing I could add would be to pay close attention to which way the 2 front seals come out/go in.. there are several different configurations they can go in..
Old stuff, have u tried bleeding off the fuel AT THE INJ PUMP bleeder screw…(5/16) by the name plate.?? It might be building up pressure at the return line.. from dirty filters..or if it has the black “olives”, it may have split apart and covering the hole.. Another thought is, if u have a pressurized side cover on the pump, it may have a partially clogged port..?? Good luck
Thanks, I’ll try changing the filters.
As you know , one has to make 100% sure that the little solenoid on the bottom of the pump is getting 12v and the plunger is opening to let fuel flow. If in doubt , hot wire 12v to the solenoid as you did or go a step further and unscrew the solenoid and remove the plunger. There should be a manual shut-off lever on the top of the pump because of course without the plunger, the electric , engine shutoff is no longer working. Some folks get rid of the electric shutoff and put in a simple pull/push cable and knob. When in doubt about any air in the system, there is no harm in to start way upstream at the fuel filter and move along thru all the various connections and bleeding points thru to the injectors bleeding out air as you go.
The plunger in the solenoid is removable in the older style solenoids.. Just watch out for the tiny return spring.. U can take the solenoid out, remove the plunger and spring and screw the body back into the pump..& use the manual s/o on the top cover if/when it starts.. Good luck