Install of New F1 Pump/Motor and Air Purging

F1 Pump/Motor Replacement and System Air Purging


I recently purchased from Juri Gelovani an upgraded transmission motor with a 360 degree wrap-around heat sink and an upgraded pump. The kit Juri supplied also included a 50 amp fuse and relay plus three round mounting bolts to replace the OEM hex bolts.

I found the instructions that Juri posted for the swap-out to be somewhat lacking based on my experience. To aid any forum members that wish to do this install, I compiled how I went about changing the pump/motor and purging the system of air.

Unlike Juri’s vehicle, I had to remove a black plastic panel and a separate panel covered in a silver heat resistant coating (I later refreshed the coating on this panel with silver colored, engine temperature rated paint) to gain access to the pump/motor. In removing the hardware that secures the black plastic panel, be careful because if you drop anything it will likely end up falling to rest on the fiberglass underbody panel which will require the removal of the underbody to retrieve the lost hardware.

I also found it necessary to remove both taillights. To assure easy recovery of any hardware you may drop when removing the washers and nuts, cover the area underneath the taillights with paper towels

As Juri instructed, construct a two-wire harness to supply 12 volts to the new motor. As I felt the need for a separate battery superfluous considering the battery in my truck would suffice, I soldered red and black alligator clips to the ends of about 15 feet of 16 gauge red and black wires. I used 14-16 gauge female, spade-type wire terminals (for connection to the new motor harness) at the other end of the wires. I purchased a small knife switch from Lowe’s which I placed in-line with the red wire near the motor terminals.

1. Turn the vehicle’s battery switch to “off.” Unplug the electrical wire connector to the existing motor.

2. Remove the screw holding the bracket that secures the motor harness to the chassis. This was a real struggle as the screw in my vehicle was tightened with more torque than I could apply with a Torx screwdriver to break it free. Ultimately, I needed to use a set of locking pliers to remove the screw.

3. Remove as much hydraulic fluid from the pump reservoir as possible. I used a kitchen syringe for this task.

4. Loosen the three hex bolts securing the motor to the chassis but do not remove them.

5. To prepare the pump for the draining of hydraulic fluid, I cutoff the bottom of an empty, two liter plastic bottle. I left the sides about 1.25 inches tall. Apply a liberal amount of paper towels under the pump as well as under the bolts securing the motor to the chassis. Slide the tray under the pump.

6. Loosen the clamps on the rubber hose that connects the black hydraulic fluid reservoir with the pump inlet. Remove the hose on the pump slowly, allowing fluid to seep past the nipple attached to the pump. As the catch tray begins to fill, push the hose back on the nipple. Empty the tray and repeat until no more fluid exits the nipple.

7. As the hose is removed, you will see a white plastic filter sticking out of the nipple. After carefully removing the hose, gently pull out the filter and set it aside on a clean paper towel. Unbolt the nipple from the pump, saving the copper crush washer for reuse. I was able to renew the washer by burnishing both sides with 2000 grit wet or dry sandpaper.

8. Replace the basin under the pump and repeat the above process for the high pressure, metal output pipe. The restraining nut that secures the pipe to the pump has been fastened with a great deal of torque. I was able to break the connection with an 8 inch long, 13 mm wrench. Allow the fluid to fill the basin and empty it as necessary as you unscrew the nut.

9. Place a rolled up towel under the existing motor to support it. Remove the two hex bolts on the left side of the motor. Remove the third bolt under the motor. Remove the metal output tube. I found it necessary to bend the tube upwards a small amount to remove the pump/motor assembly. Place a Ziploc bag around both the black rubber hose and the metal output pipe. Secure the Ziploc bag loosely with some tape or a rubber band.

10. Prepare the new pump as follows: Remove the white plastic caps protecting the ports. Use silicone spray to flush both ports on the new pump. I inserted and loosely tightened the nipple to loosen any machining burrs on this port. After removing the nipple, I flushed the port again with silicone.

11. Place the new pump/motor assembly on top of the rolled towel. Evaluate how much the metal tube must be bent back to return it to its previous position. This process is critical as you want to have the holes in the pump/motor assembly line up with the female connectors on the chassis as the nut securing the metal tube is tightened and the pump/motor assemble is drawn towards these fasteners. I found that having removed both taillights and sighting through the empty taillight holes greatly aided this process. When you have found the correct relationship between the new pump/motor to the chassis connectors, remove the Ziploc bag and tighten the output pipe nut to the pump a few turns. Back the nut out and flush the pump port again with silicon. Rest the nut in the pump port.

12. Screw a round bolt (the OEM hex bolt will not fit) supplied by Juri a couple of turns into the female fastener on the chassis that sits under the motor. Slide the motor’s heat sink over this bolt, keeping the flat washer and lock washer to the outside of the heat sink. Tighten this bolt loosely. Re-evaluate the relationship of the pump/motor assembly to the left-most chassis fasteners. Finally, make sure the electrical cable from the motor is free to move on top of the motor.

13. Flush the threads of the input nipple with silicon. Place the copper crush washer over the threaded portion and screw the nipple to the pump. Tighten with an open end wrench. As this is a lower pressure connection, tighten to a point of moderate resistance. Flush the white plastic filter with silicone and insert into the nipple. Carefully slide the black rubber hose over the filter and on to the nipple. Tighten both upper and lower hose clamps.

14. Connect the previously prepared wire harness -- with the knife switch open -- to both the new motor and the auxiliary battery.

15. Fill the reservoir ¾ full with hydraulic fluid. I used Valvoline ATF Dex/Mercon LV in the red bottle. Close the knife switch 3 times for about a 3 second interval while closed. Catch the fluid that leaks past the output pipe. Monitor the fluid level in the reservoir and in the catch basin. Begin to tighten the nut a few turns at a time and repeat the process. As you gradually screw the nut into the pump, the holes in the pump/motor assembly will begin to align with the female fasteners on the chassis. At some point, the distance will have closed to the point where you can install the remaining two round bolts -- once again, the OEM hex bolts will not fit -- through the holes in the pump/motor assembly to the female fasteners on the chassis. Loosely tighten these two bolts. As you work through this process, you will be grateful for the carpet of paper towels under the new pump.

16. When you have reached the point where no more fluid leaks past the restraining nut, disconnect the wire harness from the motor. Clean the area with a degreaser; I used Windex. Continue to tighten the nut. At some point, wrench interference with other parts in this space will require shorter and shorter wrenches ending with a 4 inch long, 13 mm wrench in order to continue. It will take a good deal of effort to tight this nut sufficiently, which will be determined when the vehicle is started to evaluate whether there is any fluid leakage. Keep in mind that some fluid will collect inside the restraining nut. Thus, the nut may be tight enough to secure the connection, but some fluid may continue to weep from inside the restraining nut. I found that this was a trial and repeat process taking a number of days as I finalized the pump/motor install.

17. Plug the new motor into the chassis electrical harness. I found it impossible to remove the bracket on the old motor harness. Therefore, I decided to abandon it and used instead a plastic wire tie to secure the pump harness to the chassis. I used a second plastic tie to secure the chassis cable to other cables next to it.

18. Install the fuse and relay provided by Juri into their respective sockets underneath the carpeted enclosures behind the seats.

19. Turn the battery switch "on"

20. Fire up the engine. The F1 fault light is likely to be “on.” This is to be expected. If the warning light is not illuminated, I recommend you complete the following steps to renew most of the hydraulic fluid. The next steps will describe how I purged the system of introduced air. It is best to have a helper although the procedure could be accomplished singly. Turn off the engine.

21. With a cold engine, remove the air cleaner cover and filter from the passenger side location.

22. Procure the following items: a. An empty one gallon plastic milk jug. b. Approximately 8 feet of rubber gasoline tubing with an inner dimension of about 0.25 inches.

23. Place the empty gallon jug in the well of the passenger air cleaner. Place one end of the hose in the jug about half way down. Place a number of paper towels under the hydraulic system service nipple on the chassis frame. Remove the rubber cap on the nipple. Attach the other end of the hose to this nipple after coiling the excess hose and placing it inside the air filter well.. Secure the rubber hose to the nipple with a plastic tie. Break the nipple connection with an open end wrench. Close the nipple.

24. Restart the engine. Slowly open the nipple. A mixture of air and fluid will flow into the gallon jug. It takes but a quarter turn on the wrench to get good flow. Monitor the fluid level in the reservoir. When the level drops to top of the white circular disk, close the nipple. Refill the reservoir and continue with the above sequence. I never let the fluid level in the reservoir drop below the white circular disk. Depending on how much air has entered the hydraulic system, the amount of new fluid it will take to achieve a clear flow will vary from case to case. I used 2.5 quarts of fluid to get the clarity of flow I desired. When a clear flow has been achieved, the dash warning light will go out. Tighten the nipple and shutdown the engine.

25. Remove the purging apparatus. Set the hydraulic level in the reservoir to 5 mm above the circular disk. Clean the area of any hydraulic fluid, paying particular attention to the underside of the pump output tube restraining nut. Replace the air filter. Reinstall the two taillights. Remove all paper towels.

26. After checking the engine bay for any tools or other foreign items, close the lid. Restart the engine and while parked, check that the transmission can be shifted into first and second gears. Perform a road test and confirm that the transmission can be shifted into all gears.

27. After an appropriate interval to allow the engine to cool, reset the purging apparatus and flush another quart of fresh fluid through the hydraulic system. Reset the fluid level in the reservoir to the 5 mm mark. Retighten the pump output tube restraining nut if necessary. You may find it necessary to do this a number of times. Recall the guidance in step 14.

28. Reinstall any hardware that was removed. Reinstall the access panels. Fin.

I found the transmission to shift a bit more “smartly” after completing the installation of the pump/motor upgrade although I acknowledge that this observation may be due to my own conceit. However, whereas it took 9-11 seconds for the system to pressurize when opening the driver’s door, it now took about 1.5 seconds for this to take place. Another possibility for what I observed was simply fluid renewal.

This install was more difficult than I expected principally because of the confined area -- the black pit of hell -- where the pump/motor is located. A robust supply of ¼ and 3/8 sockets and other socket hardware are needed as well as three different lengths of 13 mm wrenches. LED flashlights and a two foot long “grabber” for retrieving dropped hardware are also quite useful. There is no reason to rush the install as this is when parts fall into oblivion, notwithstanding the fact that you have laid a carpet of paper towels to catch any dropped hardware as well as for soaking up hydraulic fluid drips.

Cheers..

Jim

Attached Pictures:

1. View of Test Harness Connected to Motor
2. View of Installation from Taillight Holes
3. View of Setup for Air Purging
4. View of Renewed Heat Shield.

 

Yes, this is correct.

 

Congratulations!

After I had removed the old pump/motor, a family issue caused a three week interruption in the installation of the new pump. The Ziploc bag I placed around the two pipes captured a significant amount of fluid that leaked from the output pipe. When I fired up the engine upon completion of the install, I immediately got the F1 dash warning light, and this demonstrated to me that that it would be necessary to purge the system of air.

It would appear that your experience mirrored that of Juri Gelovani when he swapped out his pump. The key to your combined success appears to be limiting the amount of fluid that leaks from the output pipe.

I felt great after my successful test drive. More than anything in my ownership experience to date was the success of this project which truly confirmed my "ownership" of the vehicle.

 

Thank you!

Your work with the F1 system -- going back to the time when you took an F1 motor apart and found the conductive goo that caused the motor to fail -- gave me the self confidence to tackle the change out to the upgraded motor and pump. I am grateful for the work you did and continue to do.

I had my own unique experience with a motor that had failed. In my case, water had caused the armature of a starter motor from a Honda motorcycle to rust and seize. On little more than a prayer, I took the motor apart and cleaned it with starter fluid. To my surprise, it worked! Little successes as this one and great teachers like yourself inspire one to tackle new projects.