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Took it apart, cleaned the reservoir, cleaned the pump and the motor and reassembled. Primed, it will send fluid out the bleeder valve. But once assembled and put back in the car it will not build sufficient pressure to trip the pressure sender switch(new switch). Will run without appearing to labor so the assumption is it is not building enough pressure.
Have read all the relevant threads on rebuilding and such.
So, the questions are as follows:
How to determine if the motor is weak and unable to build proper pressure?
The pump is comprised of a pressure vessel, offset pump with three pistons and ball bearings that depending on where they are in the stroke allow brake fluid to pass into a cavity through the piston and past the ball bearing whereas during the rest of the stroke the ball bearing blocks fluid. (Feel free to correct)
Is the piston also supposed to move in tandem with the ball bearing or should it be stationary as the pump spins?
If the pump is ok, then my assumption is that something else is preventing pressure from being built up. Like air. The bleeder valve passes fluid without bubbles. But, when I separated the motor from the pump there was plenty of bubbles in the pump. Is this an issue?
Could the fluid simply be passed back to the reservoir therefore never building pressure?
Any guidance is appreciated. I am ready to send the unit for exchange, but I really want to understand more about the underlying issue.
Took it apart, cleaned the reservoir, cleaned the pump and the motor and reassembled. Primed, it will send fluid out the bleeder valve. But once assembled and put back in the car it will not build sufficient pressure to trip the pressure sender switch(new switch). Will run without appearing to labor so the assumption is it is not building enough pressure.
Have read all the relevant threads on rebuilding and such.
So, the questions are as follows:
How to determine if the motor is weak and unable to build proper pressure?
The pump is comprised of a pressure vessel, offset pump with three pistons and ball bearings that depending on where they are in the stroke allow brake fluid to pass into a cavity through the piston and past the ball bearing whereas during the rest of the stroke the ball bearing blocks fluid. (Feel free to correct)
Is the piston also supposed to move in tandem with the ball bearing or should it be stationary as the pump spins?
If the pump is ok, then my assumption is that something else is preventing pressure from being built up. Like air. The bleeder valve passes fluid without bubbles. But, when I separated the motor from the pump there was plenty of bubbles in the pump. Is this an issue?
Could the fluid simply be passed back to the reservoir therefore never building pressure?
Any guidance is appreciated. I am ready to send the unit for exchange, but I really want to understand more about the underlying issue.
K
Yes, pistons need to move.
Getting these things to prime is the hardest part of the whole job. You're certain it is primed?
I put the pistons in backwards once....it would pump, but not build enough pressure. Double check that.
Here's the PSD unit on the bench, so to speak. New hoses and clamps - added blue locktite.
Besides the new hoses, i poured brake fluid into the pump and let it sit there while I spun the pump to lubricate the ball bearings and hopefully pull air out of the pump.
I'll prime/bleed it like I did originally. If it does not sound like the motor is laboring after a few minutes I'll like box it up send it off for exchange.
FWIW, the pump primed immediately. I attribute it to filling the pump cavity and letting it sit before bolting the motor in place. I have bled the air from the system
Now, my question. Should the orifice to the slave show fluid filling the hole? Shown here:
Still no love. Pump never stops. I am wondering if the fluid is simply passing through the Trans.Valve Block (no idea how it works, honestly) so insufficient pressure builds up. I tested the operation of the switch that releases brake fluid to the slave and I could hear it click when I applied 12 volts to it.
Can the trans valve lock pictured below (#9) go bad? Can it be tested for leaking fluid back to the reservoir?
Last edited by Kevin in Atlanta; 11-06-2017 at 09:45 AM.
Cannot get my head around why the unit will not build sufficient pressure. Even on the bench the motor never labored.
I has assembled it twice. Verified the assembly. I wish I had a pressure gauge I could use in place of the bleeder screw to verify what pressure is being made.
For all I know the relief valve in the distribution block is partially open allowing some of the pressure to bleed off back to the reservoir.
Or maybe a weak ground preventing a full 12volts to create pressure. Long shot, I know.
When I energized the motor after reassembly the unit pushed out all the air quickly. If it were not primed no fluid would be moved - at least that is what I believe. I move fluid.
Open to any suggestions. I am more than willing to get a rebuilt unit from Roger, but it would be embarrassing and $$$ if it turned out to be something I could fix myself.
I would install the unit in the car plug it into the car harness and follow the bleeding instructions I posted.
my guess is that the solenoid on the side of the assembly is not closed so the pump will never reach its shut off point
10-16-2017, 01:00 PM
Bench testing PSD System
