Question about Cars & Trucks
Air is detectable in hydraulic system. Control valve rebuilt, all hoses replaced,and spider (U joint) between engine an pump replaced. Now no hydraulic pressure
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Posted on Jan 02, 2017
SOURCE: I have a ford 1710
I had this problem too. I made the upgrades like you did,
but I kept blowing seals. The solution is really simple, it
seems that if you take it to a shop they figure it out right
away. Where is all this information stored anyway?
One of the screws on the plate holding the power steering
hydraulic diverter (below the pump) needs to have a washer
between the plate and the engine. I don't remember which one
it is but I think it might be the top one. This will bring the shaft
on the priority valve (same as diverter) in line with the seat
on the pump. Without it they are not quite lined up leaving
a gap for the fluid to shoot through and blow the seal. Also,
makes it harder to get the thing together.
Posted on Aug 14, 2008
SOURCE: 67 mustang GTA steering problem
THESE TYPE CAN TRAP AIR DURING REFILLING, TRY REMOVE CAP ON PUMP, START ENGINE, SLOWLY TURN STEERING WHEEL, RIGHT - LEFT, CHECK FLUID FREQUENTLY WHILE DOING THIS, THIS SHOULD PURGE SYSTEM OF AIR .
Posted on Oct 05, 2008
SOURCE: 2004 Mazda RX-8 PO455
It will not go off by itself,you will need to reset it by connecting to a diagnostic tool.Once cleared if there is any other problem then it will trigger the check engine light again.Hope this helps..
Posted on Sep 03, 2009
YOU CANT USE A REGULAR FUEL LINE ON POWER STEERING AS A HIGH PRESSURE HOSE.BECAUSE POWER STEERING PRESSURE IS 1000 PSI.YOU HAVE TO BUY THE POWER STEERING HIGH PRESSURE HOSE IT HAS NUMBER OF PLIES MATERIAL WEAVES TO MAKE IT STRONG.IT WAS MADE FOR POWER STEERING HIGH PRESSURE.YOU DONT HAVE A BLOCKAGE .THE HIGH PRESSURE HOSE JUST WORE OUT.REPLACE IT .IT SHOULD FIX THE PROBLEM.
Posted on Sep 04, 2009
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EVAP Leak Detection Pump Description & Operation
The evaporative emission system is designed to prevent the escape of fuel vapors from the fuel system. Leaks in the system, even small ones, can allow fuel vapors to escape into the atmosphere. Government regulations require onboard Testing to make sure that the evaporative (EVAP) system is functioning properly. The leak detection system tests for EVAP system leaks and blockage. It also performs self-diagnostics. During self-diagnostics, the Powertrain Control Module (PCM) first checks the Leak Detection Pump (LDP) for electrical and mechanical faults. If the first checks pass, the PCM then uses the LDP to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out. The PCM determines the size of the leak based on how fast/long it must pump the LDP as it tries to maintain pressure in the system.
The main purpose of the LDP is to pressurize the fuel system for leak checking. It closes the EVAP system vent to atmospheric pressure so the system can be pressurized for leak Testing. The diaphragm is powered by engine vacuum. It pumps air into the EVAP system to develop a pressure of about 0.25 psi. A reed switch in the LDP allows the PCM to monitor the position of the LDP diaphragm. The PCM uses the reed switch input to monitor how fast the LDP is pumping air into the EVAP system. This allows detection of leaks and blockage.
The LDP assembly consists of several parts. The solenoid is controlled by the PCM, and it connects the upper pump cavity to either engine vacuum or atmospheric pressure. A vent valve closes the EVAP system to atmosphere, sealing the system during leak Testing. The pump section of the LDP consists of a diaphragm that moves up and down to bring air in through the air filter and inlet check valve, and pump it out through an outlet check valve into the EVAP system. The diaphragm is pulled up by engine vacuum, and pushed down by spring pressure, as the LDP solenoid turns on and off.
The LDP also has a magnetic reed switch to signal diaphragm position to the PCM. When the diaphragm is down, the switch is closed, which sends a 12v (system voltage) signal to the PCM. When the diaphragm is up, the switch is open, and there is no voltage sent to the PCM. This allows the PCM to monitor LDP pumping action as it turns the LDP solenoid on and off.
Diaphragm Downward Movement
Based on reed switch input, the PCM de-energizes the LDP solenoid, causing it to block the vacuum port, and open the atmospheric port. This connects the upper pump cavity to atmosphere through the EVAP air filter. The spring is now able to push the diaphragm down. The downward movement of the diaphragm closes the inlet check valve and opens the outlet check valve pumping air into the evaporative system. The LDP reed switch turns from open to closed, allowing the PCM to monitor LDP pumping (diaphragm up/down) activity.
During the pumping mode, the diaphragm will not move down far enough to open the vent valve. The pumping cycle is repeated as the solenoid is turned on and off. When the evaporative system begins to pressurize, the pressure on the bottom of the diaphragm will begin to oppose the spring pressure, slowing the pumping action. The PCM watches the time from when the solenoid is de-energized, until the diaphragm drops down far enough for the reed switch to change from opened to closed. If the reed switch changes too quickly, a leak may be indicated. The longer it takes the reed switch to change state, the tighter the evaporative system is sealed. If the system pressurizes too quickly, a restriction somewhere in the EVAP system may be indicated.
Diaphragm Upward Movement
When the PCM energizes the LDP solenoid, the solenoid blocks the atmospheric port leading through the EVAP air filter and at the same time opens the engine vacuum port to the pump cavity above the diaphragm. The diaphragm moves upward when vacuum above the diaphragm exceeds spring force. This upward movement closes the vent valve. It also causes low pressure below the diaphragm, unseating the inlet check valve and allowing air in from the EVAP air filter. When the diaphragm completes its upward movement, the LDP reed switch turns from closed to open.
Removal & Installation
The Leak Detection Pump (LDP) is located under the left quarter panel behind the left/rear wheel. It is attached to a two-piece support bracket. The LDP and LDP filter are replaced (serviced) as one unit.
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