Repair Instructions for Kugelfischer PLO Injection Pump

This document is based on a translation of the Schaefer Einspritztechnic GmbH repair instructions - it is shared for general interest.

Please resist the urge to dismantle/repair your pump unless you are prepared to dynamically recalibrate the pump using specialist equipment -

Warning: dismantling the pump will destroy the calibration!!!

Disassembly

Screw the pump onto the clamping plate (1)(PRW - 92 920 001) so that the pump (2) is inclined about 30° around its longitudinal axis.
Unhook the return spring on the enrichment lever (1) and on the spring suspension (2). The spring eyelets must be bent slightly open for this purpose.
Remove the warm-up encoder (1) after loosening the three fastening screws (2).

Dismantle Pump body

After removing the locking washer with which one of the fastening screws (1) must be sealed, loosen three of the four screws. Enter the seal number in the work or warranty card.
When unscrewing the last fastening screw (1), press the pump body (2) against the pump housing by hand (pressure of the piston springs!)
When removing the pump body (2), tilt the pump body (1) diagonally downwards so that the pistons cannot fall out of the guides.
Remove the pump body seal.

Disassemble the Pump body

Pull the piston (1) with the spring plate and piston spring (2) out of the guide.
The pistons are drawn on the spring plate (3).
Pull the cone spring (1) completely out of the guide hole.
Remove pressure valves: clamp the pump body (use protective jaws)) and screw the pressure valve (1) out of the pump body with a ring wrench. The pressure valves can be exchanged with each other. Pay attention to cleanliness!
Remove suction valves: Use a hex wrench to unscrew the pressure screw (1) above the suction valve from the pump body.
Using the suction valve lifter (1) (PRW 92 922 120), lift the suction valve (2) out of the bore. To do this, the PRW is spread with the flattened end in the suction valve opening. Unscrew the damping valve (1) with a ring wrench and carefully set it down, protected against dirt.
Unscrew the damping valve (1) with a ring wrench and carefully set it down, protected against dirt.
Loosen the banjo screw (1) and remove the double connection (2).
Remove eccentric with regulating swingarm: Pull the fixing pin (1) for axial fixation of the eccentric (2) out of the fitting hole.
Pull eccentric (1) complete with lever from the guide bushing (2).
The enrichment and warm-up levers are only unscrewed if they are defective.
Remove the corrugated disc (1), if it has not remained in the pump housing, from the eccentric.
Remove the swing arm (1) from the pump housing.
If the corrugated disc has not been pulled out of the pump housing with the eccentric, it must be removed from the housing.
Disassemble Regulator:

After removing the sealing disc on the end cover (.1), loosen the three fastening screws and remove the end cover by tapping lightly with a plastic hammer (do not use a screwdriver). Remove the seal.
Use a multi-tooth wrench to loosen the jaw (1).
ATTENTION! Spring spiral (2) has preload
Insert the dowel pin (2) (PRW 92 920 902) into the 5 mm bore of the regulator gear (1), push the regulator gear in the direction of the stop until the dowel pin engages with the bore of the bearing shield.
Use a hexagon socket wrench to loosen the clamping screw (3) of the spring gear.
Spring spiral (1) on the small diameter and spring gear (2) complete from the toothed shaft (3).
Remove the retaining ring (1) for axial fixation of the spring spiral (2).
Spring spiral (1) at the smallest diameter and pull from spring gear (2).
Remove the retaining ring (1) for axial fixation of the regulator gear (2).
To remove the regulator gear, screw (1) two screws (2) M 6 x 25 with a long thread alternately into the threaded holes of the regulator wheel until the regulator gear is pressed by the control shaft.
Flat wedge from the slot of the control shaft.
Use a hexagon wrench to loosen the fastening screw (1) of the bearing plate (2).

Remove the clamping bush (3).
Pull the bearing shield (1) with control shaft (2) out of the pump housing. Pay attention to the adjustment discs between the rear ball bearing and the control shaft.
To remove the control cam (1), press the regulating lever (2) in the direction of neutral, until it stops.
Lift the regulating cam slightly at the ring groove (3) until the ball head of the ball pin no longer engages with the ring groove of the regulating cam. The control cam can now be pulled out of the pump housing.
Fixing screw (1) for axial fixation of the toothed shaft (2) with hexagon socket wrench unscrew.
Pull the toothed shaft (1) complete with ball bearing (2) out of the pump housing. If the ball bearing seat is too tight, a plastic mandrel can be used from the cam shaft chamber by lightly tapping the tooth shaft.
Remove the large retaining ring (1) from the pump housing.
ATTENTION! Before removing the camshaft (2), it is necessary to raise the sliding tappets.
Attach tappet holder (1) (PRW - 92 924 002) with the two screws. (2) Attach to the open side with shorter tube ends (3) pointing towards the tappets (4). The lettering of the PRW points upwards.
The tubes (1) of the tappet holder are pushed over the sliding plunger under preload of the tension spring.
To lift the tappets, the measuring wire (1) (belongs to the PRW) is held from the regulator side with the angled end, between the cam track and the tappet. Turn the camshaft (2) to the left until the measuring wire is pulled between the slide tappet and the cam track. This pushes the tappet upwards against the pump housing. In this way, the remaining tappets are lifted individually.
Screw the camshaft extractor (1) (PRW - 92 924 003) with the two bolts (2) into the threaded fittings of the clamping flange (3). Turn the coil bushing (4) onto the camshaft boom (5). Hold the hexagon bolt (6) against it and pull the camshaft with ball bearing out of the housing by turning the nut (7) to the right.
Remove the retaining ring (1) for axial fixation of the ball bearing (2) and press the ball bearing from the camshaft (3).
ATTENTION! The speed sensor installed in the camshaft must not be pulled out of the camshaft. Pay attention to speed sensor sprockets.
From the camshaft chamber, press the tappet against the pump housing by hand, then pull the relevant tube (1) from the tappet (2). Remove the tappet with spring from the housing. Remove the remaining tappets in the same way. Remove the perforated plate that is included under the ram springs.
Remove the Throttle Lever: Using a socket wrench (1) (PRW 92 924 101), unscrew the
ball pin (2) from the regulating shaft (3).
Regulating shaft (1) complete with regulating lever(2) pulled out of the pump housing. Pay attention to the tuning disc in the housing. If the radial sealing ring (3) is not pulled out, it must be removed with the help of a screwdriver. Remove the washer that sits between lever (2) and radial sealing ring (3).
Remove the regulating cone: Loosen the fastening nut (1), then press open the slotted clamp (2) with the help of a screwdriver. Pull the regulating lever (3) from the shaft (4).

Assembly of the Pump

All removed parts must be cleaned before assembly and checked for possible wear by means of a visual inspection.
All moving parts, except the speed sensor, must be easily oiled before installation. The prescribed tightening torques must be observed.

Installing the regulating shaft

Push the regulating shaft (1) into the guide bush (3) with the flattened end (2).
From the side of the pump, slide a thrust washer (1) over the regulating shaft (2).
Insert the ball pin (1) into the socket wrench (2)(PRW- 92 924 101).
Turn the regulating shaft so that the flattened side (3) points upwards. Screw in the ball pin. (1.0 kpm)

Installing tappets:

Tappet retainer (1) (PRW - 92 924 002) has the two fastening screws opposite the eccentric side on the pump housing screws.
The fastening must point upwards.
Grease the perforated plate (1) a little and insert it from the regulator side over the pins of the tappet guides.
Tappet (1) with spring (2) from the regulator side, by hand, into the tappet guide.
Clip the tube opposite the inserted tappet (1 ) over the tenon (2) of the sliding plunger.
The sliding plunger held in this way must remain in its uppermost position without any counter-holding.
In the same way, the other tappets are inserted and held in their uppermost position.

Installing the camshaft:

Press the ball bearing (2) onto the camshaft (1) and secure it axially with the retaining ring (3).
ATTENTION! The speed sensor must not be damaged
Push camshaft (1) completely from the clamping flange into the camshaft chamber.
If the ball bearing goes too tightly into the pump housing, the camshaft can be pressed into the housing with the help of the camshaft puller (1). The hexagonal nut (2) is placed under the flat iron (3) and the screw (4) is screwed in.
By inserting the retaining ring (1), the ball bearing (2) and thus the camshaft (3) are axially secured.
Slide the mounting sleeve (1) (PRW - 92 924 053) over the camshaft stub and insert the new radial sealing ring (2).
Remove slide plunger holder and check the camshaft for smooth operation.
The protective sleeve (1) can also be used for press-fitting the camshaft instead of the camshaft puller.

Assemble the controller:

Insert the control cam (1) with the small diameter into the pump housing.
Turn the regulating shaft (2) in the direction of idle. Lift the control cam until the ball head of the ball pin engages with the ring groove of the control cam.
To the short, offset end of the control shaft (1) put the intended shims (2) back with them.
Check the key/wedge (3) for tightness and replace it if necessary
Push the control shaft into the control cam (2) with the short end (1). The control shaft should slide easily in the control cam, but must be radially free of play.
Press the ball bearing (2) onto the short end (1) of the regulator shaft, paying attention to the shims(3).
Press the control shaft (1) into the pump housing with ball bearings (2).
On the slotted end of the control shaft (1) press the ball bearing (2).
Slide the bearing plate (1) onto the ball bearing (2) and into the pump housing. Turn the bearing shield so that the crescent-shaped countersink (3) of the stop (4) coincides with the countersink (5) in the pump housing.
Insert the clamping bushing (1) into the countersink with the unscrewed side facing forward and tighten it with the fastening screw (2) (0.6 kpm)
The axial clearance of the control shaft (1) of hand testing. With the help of the shims, the control shaft must be axially tuned without backlash.
Press the toothed shaft (1) completely into the bore (2) of the pump housing.
ATTENTION! Toothed shaft is only used completely (with ball bearings) as a spare part.
Screw in the fixing screw (1), making sure that the offset end (2) of the fixing screw engages between the two ball bearings of the toothed shaft (3).
Regulator gear (1) on the slotted journal (2) of the control shaft. The collar of the regulator gear points to the regulator shaft.
ATTENTION! Pay attention to undamaged tooth mesh with tooth shaft (3).
Turn the control cam (1) until the keyway (2) of the control cam points vertically upwards.
Hold the control cams by hand in this position.
Turn the toothed shaft (1) to the left until the impact pin (2) of the regulator gear (3) strikes at the stop of the bearing shield.
Regulator gear (1) with retaining ring (2)axially secure.
Toothed shaft (3) from stop to stop turning and paying attention to smooth running.
The spring gear (1) is slotted throughout at the collar (2),
When inserting the spring spiral, it is irrelevant in which half of the slot the angled spring end is inserted.
Insert the spring spiral (1) into the slot with the short-angled end (2) in such a way that the spiral runs counterclockwise from the centre.
Push thrust washer (1) onto the collar (2) of the spring gear so that the curved edge points outwards.
Secure the spring spiral (1) and thrust washer (2) with the retaining ring (3).
The washer (2) is pushed onto the toothed shaft (1). For toothed shafts that have a flange, the washer is not required.
Push spring gear {1) completely on the tooth shaft (2). Respect tooth mesh with speed sensor pinion (3) .
Press the clamping piece (1) with the dowel pin into the provided fitting hole (3). The flattened side (3) of the clamping piece points to the spring gear (4). The groove (5) to accommodate the spring spiral points forward.
Clamping jaw (1) with countersunk screw (2), screw lightly onto the clamping piece (3). The dowel pin (4) on the clamping piece ensures the correct angular position of the clamping jaw.
Turn the control cam until the keyway points upwards. Hold the control cam in this position and turn the spring gear to the left until the spring end (1) is 90° in front of the spring clamp (2). Hold on to the spring gear, screw the clamping screw (3) into the toothed shaft and tighten it slightly.
The free end (1) of the spring spiral is first inserted between the spring clamp (2-),. (clamping piece and clamping jaw);
Push the free end (1) of the spring spiral through the spring clamp (2) so that the spring end protrudes approx. 3 - 4 cm.

Tighten the countersunk screw (3). The spring spiral must be perfectly positioned in the two grooves (2) of the spring clamp.
Install eccentric with regulating swingarm: Replace the T-shaped sealing ring (1) of the eccentric (2) as a matter of principle.
Insert the eccentric into the bushing (1) and push the corrugated disc (2) onto the eccentric shaft with the curved side.
Insert the regulating swing arm (1) into the pump housing so that the two Phillips screws (2) point upwards.
Insert the eccentric into the regulating swingarm (1) and fix the eccentric with the stop pin (2), which engages in the groove of the eccentric through the hole (3).
Installing and adjusting the regulating lever: Press in or drive in a new radial sealing ring with mounting sleeve(1) (PRW - 92 924 051).
Slide washer (1) onto the regulating shaft (2).
Press the regulating lever (1) onto the regulating shaft (2), but do not tighten it yet.
Insert the adjustment piece (1) (PRW - 92 923 001) into the ring groove (2) of the control cam.
Place the regulating swingarm (1) on the regulating cam and press the regulating cam lightly towards the clamping flange with the help of a 4 mm Allen key (2). The adjustment piece must then lie on the stylus bolt (3) of the regulating swingarm without play.
Fix the regulating lever (1) with dowel pin (2)(PRW - 92 920 900) in the fitting hole (3) on the pump housing to the idle position. The control cam, with the adjustment piece, is easy to press against the stylus bolt of the regulating swingarm with the Allen key (4).
Push the regulating lever (1) outwards with the help of a screwdriver (2). To do this, the screwdriver is placed on the groove (3) of the regulating shaft and pressed lightly against the regulating lever. Tighten the regulating lever on the regulating shaft (4). The regulating shaft must run smoothly without axial backlash. Remove the adjustment piece from the control cam!
Hub Tuning:

Screw screw (1) M 6 x 25 with long thread into the regulator gear (2). Turn the regulator gear with the dash mark (3) (single dash) so that the dash mark coincides with the setting mark (4) on the pump housing. Turn the screw (1) slightly against the bearing shield until the regulator gear remains fixed in this position.
The regulating lever (1) must remain fixed during stroke adjustment.
Measurement example:
Measured stroke with original ball inserts:
Element 1 2 3 4 . . .
0,61 0,68 0,61 0,61
Remove the ball insert (2) to be tuned from the control swingarm and insert a 4.00 mm measuring ball insert for this purpose.
New stroke for element 2 with 4.00 mm measuring ball insert: 0.70 mm (1)
The stroke difference to the tuning stroke (= the stroke to which all elements are to be tuned in our example 0.61) is: 0.70- 0.61 = 0.09 mm.
This results in the ball insert to be used:
4.00 mm measuring ball insert
+ 0,09 mm Hubdifferenz
4.09 mm = New ball insert
With minus stroke (= stroke that is smaller than tuning stroke) it is easier to lap the ball insert onto the tuning stroke if the stroke difference is not greater than -0.05 mm. For lapping, the ball insert is lapped off with the ball shape (1) facing upwards on a squeegee (2).
Before inserting the ball insert, it must be cleaned well.
If the stroke is coordinated from element to element, the ball inserts (1) are secured with the retaining plate (2).
Insert the spring holder (1) (PRW - 92 923 011) into the threaded holes below the eccentric (2).
Attach the mainspring (3) of the PRW to the enrichment lever (4).
Dial gauge (1) (PRW - 92 921 002) with the help of the adjuster (2) (PRW-92 921 501). set to "zero".
For stroke adjustment from element to element, place the guide plate (1) (PRW - 92 921 004) with dial gauge (2) on the pump housing. Camshaft spin. The stroke should not deviate from the basic stroke by more than 0.10 mm (see test sheet of the pump in question for the basic stroke).
If the useful stroke difference between the individual elements is more than 0.05 mm, the stroke shall be adjusted by measuring and replacing the ball inserts (1) concerned. For this purpose, the retaining plate (2) must be removed after loosening two Phillips screws (3).
If the tuning stroke is not equal to the basic stroke, the basic stroke specified in the respective test sheet shall be adjusted on the enrichment screw (1). Then remove the screw on the regulator gear and the dowel pin on the regulating lever.

Assembling the pump body:

Clamp the pump body (1) with the flat side facing downwards. Insert the sealing disc into the suction valve bore (2) and insert the suction valve (3) into the suction valve bore with the flanged side up. The suction valve lifter (4) can be used for this purpose.
Pay attention to cleanliness!
Pull a new round cord ring (2) onto the screw connection (1) of the suction valve (but not over the thread). Grease the countersink for the screw in the pump body.
Screw the screw connection (1) into the suction valve bore with a hexagon socket wrench (2.0 kpm).
Place a sealing disc in the pressure valve bore (1) of the pump body and screw in the pressure valve (2).
Pay attention to cleanliness!
Screw the pressure valve (1) with a ring wrench (2.5 kpm).
Insert a sealing washer (1) into the hole for the damping valve. (Oil filler plug 4 side). Damping valve (2) with a new round cord ring (3).
Tighten the damping valve (1) with a ring wrench (2.0 kpm). When screwing in the damping valve, make sure that the round cord ring is not crushed.
Slide the piston (2) with spring plate (3) and piston spring (4) into the piston guide (1).
The pistons are numbered on the spring plates, namely pistons I, II, III . . the last piston has no number. The piston I is basically located on the fuel inlet — opposite the damping valve.
Pay attention to cleanliness!
Press the cone spring (1) with the larger diameter into the receiving hole (2).
Screw on the pump body:
Clamp the pump at an angle of approx. 30° around the longitudinal axis. Place the gasket (1) on the pump housing with a little oil. The oil inlet hole (2) in the pump housing must not be covered by the seal.
Hold the pump body (1) at an angle so that the pistons (2) cannot fall out of their guides. Allow the piston to sit on the swingarm (3), then press the pump body onto the pump housing. The damping valve (4) points in the direction of the regulator side.
Press the pump body firmly onto the pump housing by hand until the first fastening screw (1) is tightened.
Aluminium discs are to be added under the fastening screws. Tighten the pump body crosswise (1.0 kpm).
After tightening the pump body, check the ease of movement of the eccentric.

Adjustment & Calibration

Adjusting the Controller

Clamp the pump to the test bench and connect the oil inlet(1), fuel supply (2), fuel return (3) and injection lines.
After removing the plug screw(4), fill the pump with engine oil (100 cc).
Unplug the regulating lever (1) in the idle position with a dowel pin (2).
The individual stake-out points of the regulating lever are:
LL   =   Idling
T1   =   Partial Load 1.
T2   = Partial Load 2.
VL   =   Full load.
Note: It is envisaged that the test speed will be increased from 350 rpm to 500 rpm. In the case of regulator gears which have the necessary additional marking for 500 rpm, this marking is marked with the number 5.
Test bench from speed 0 rpm to 350 rpm. Check whether the two dash marks (1) and (2) coincide.
Start the speed at 1400 rpm and go back to 350 rpm. Check that the two dash marks (1) and (2) match.

If so:
Unplug the regulating lever in T1 and bring the test bench from 350 rpm to 1400 rpm.
Check whether the line mark (1) on the housing between the line marks (2) stands for 1400 rpm.
Speed 2800 rpm and then go again to 1400 rpm.
Check whether the line mark (1) is between the line marks (2).

If so:
Disconnect the regulating lever in VL and bring the test bench from 1400 rpm to 2800 rpm;
Check that the line mark (1) between the bar marks (2) represents 2800 rpm. If so, the slider is set.
If the regulator position at 350 rpm is incorrect, the spring preload must be changed.
For this purpose, the regulator gear (1) is blocked with the dowel pin (2) in the bearing shield. By twisting the spring gear (3) with the help of the trunnion wrench (PRW 92 926 011), the spring preload is changed accordingly.
Right-hand rotation = greater preload Left-hand rotation = smaller preload
If the regulator position at 1400 and 2800 rpm is not correct, the clamping jaw (1) must be loosened and the spring length changed.
The exact adjustment of the regulator can be achieved by alternating the spring preload and the spring length.
ATTENTION! After adjusting the regulator, tighten the clamping screw (2) to the spring axle.

Hydraulic Control

The hydraulic control (injection volume check) of the injection pump is carried out in accordance with the PLO test sheets

The regulator adjustment is carried out on the assembled pump. The pump body must be mounted, and the oil connection must be connected. Set the test bench to 350 rpm and change the spring length on the clamping piece so that the line mark for 350 rpm coincides with the MO mark on the pump housing.

After the inspection has been carried out, the oil must be drained from the injection pump via the oil filling opening of the pump body.
Screw on the end cover: Place the gasket (.1) with a little oil on the end cover (2).
Unhook the retraction spring and remove the spring suspension (PRW - 92 923 011). Press the end cover (1) onto the pump housing. The lid is fixed by the pass-through rifles (2).
Under the three screws (1) of the aluminium cover attach aluminium discs and tighten them (0.8 kpm).
One of the screws for fastening the end cover must be sealed with a locking washer.
For sealing, the stamp (1) with the KD number must be used.
Seal pump body: One of the screws for fastening the pump body must also be sealed with a locking washer.
Use KD stamps.
Full load stop: The full load stop (1) is screwed to the end cover (2) in such a way that the stop screw (3) points to the regulating lever (4).
To adjust the full load stop, the stop screw (1) must first be screwed in and the regulating lever (2) fixed with a dowel pin (3) in full load position (4). Unscrew the stop screw (1) to the regulating lever (2) as far as it will go.
Tighten the lock nut (5) and remove the dowel pin.

Complete the pump

To the. Screw on the fuel inlet side of the pump body the double connection (1) with filter screw and sealing washers. The two connections (2) point upwards.
For storage or shipping, the pressure valve fittings (1), the double connection (2), the damping valve (3), the connections of the warm-up sensor (4), the oil connection (5) and the camshaft stub (6) shall be provided with sealing caps. Oil return at the end cover (not visible in the picture) also provided with sealing caps. Insert the camshaft drive wedge (6) and secure it with a rubber ring.
The enrichment screw (7) is to be sealed with the safety cap. Next to the nameplate (8) the date of repair and the company logo must be stamped.