When fitting a new master cylinder, it is a good idea to bench bleed it before installing it in the car. This procedure will "prime" the master cylinder, making your on-the-car brake bleeding a little easier. This procedure will also keep you from flipping the square seal in the master-cylinder, which would cause yet another master cylinder replacement.
There are two ways to bench bleed your new master cylinder. One option is to reuse some old brake lines and create your own bench bleeder. Your other option is to purchase a universal bench bleeding kit at your local auto parts store. This second option is more desirable because the solid brake lines do not allow you to see the air bubbles being bled from the system. The lines will be attached to the brake line outlets of the master cylinder and looped around up to the fluid reservoir.
The premise of the procedure is simple. Move fluid slowly through the system to remove all air in the system and to fill the master cylinder with fluid. To do this, clamp the master cylinder in a vise so it is as level as possible. Fill the reservoir with clean fluid and use a large blunt tipped Phillips screwdriver to pump the piston slowly and evenly, full strokes. The air which is still in the system at this point will be bled out. Pump the cylinder until no more air bubbles are visible. Now you are ready to install the master cylinder in the car and finish bleeding the system. Following this procedure will reduce problems with the bleeding process.
While your at it, it maybe a good idea to check your brake pads and rotors just to get it all taken care of at once if you haven't done so already.
Noisy Fuel Pump? Might Be A Bad Fuel Pressure Regulator...
When diagnosing fuel pump noises (groaning), you may want to check for the Fuel Pressure Regulator. Many times the noises are caused by a faulty pressure regulator on the fuel rail and NOT by the pump. A regulator that is stuck closed can cause excessive fuel pressure, which leads to reduced fuel mileage, failed smog checks and poor running. This condition also causes the fuel pump to work too hard. If the regulator is stuck open, there could not be enough fuel pressure under higher load conditions, leading to poor running under higher loads/boost. This problem also leads to hard starting (due to lack of residual fuel pressure). In addition, a ruptured diaphragm in the regulator will allow fuel into the intake manifold by way of the vacuum hose leading to it. All of these problems will lead to poor driveability. My suggestion is to check all of these things first before diagnosing your problem as a faulty fuel pump.
Having Starter Problems?
First thought is probably battery, Right? Maybe the starter? Check the battery connections before replacing these costly parts.
Use a Digital Multimeter(DMM) measure the voltage drop. A drop of only 0.2 to 0.3 volts may be enough to reduce performance in automotive circuits. Set your DMM to the volt or millivolt scale and connect the positive lead to the side of the component nearest the battery (+) and the negative lead to the next connection in the circuit. Move backwards through the system, checking the connections. Check voltage drops between battery post and connecting cable, and both ends of the battery cable. Also check the ground side of the circuit for excessive resistance.
A good guideline is to see 100mv (.1v) per connection in the circuit. If the battery cables worn, cut or damaged, replace them.
A "click" with no cranking probably means the solenoid is being energized but there is not enough current to turn the starter over. This could be caused by discharged battery, or bad battery connections (positive and grounds). These problems are commonly misdiagnosed, and these simple checks could save a costly and incorrect parts purchase.
Installation Instructions for Spin-on Oil Filters:
Unscrew and remove old filter. Be sure old gasket is removed with filter. Wipe filter mounting base with clean cloth.
- Apply thin film of the best Synthetic motor Oil to new filter gasket. Do not use grease.
- Line up threads carefully to avoid cross-threading. Screw new filter on until gasket contacts base. IMPORTANT: Follow instructions on the oil filter for final tightening.
- Be sure oil shows full on dipstick. Start engine and check for leaks. Correct source of any leaks observed.
- Shut off engine. Re-check oil level. Add oil if necessary.
- Be sure to check the oil ratings specific for your vehicle and oil Brand comparsion before further proceeding.
Oil Filter Leakage On Volkswagen Diesel Engines
Several bulletins and warnings have been issued regarding the proper installation of the oil filter on Volkswagen Diesel engines to avoid oil leakage. This bulletin is a reminder to installers of the potential problems that may occur.
The Volkswagen Diesel was introduced in the 1977 VW Rabbit. Shortly after introduction, complaints of leakage at the oil filter began. As a result of the complaints, that continued into the 80s, the Federal Trade Commission lodged an investigation into the problem.
Their investigation focused on oil filter installation instructions and revealed that printed instructions were less than adequate. Instructions on the replacement filter and in the vehicle owners' manual were different than instructions supplied to Volkswagen dealers in the form of product circulars.
The VW product circulars recommended that oil filters be tightened with a band-type wrench three-quarters turn past initial gasket contact. They went on to say if the oil filter gasket tends to be "pushed out" after the filter is tightened as instructed, it would be necessary to replace the oil filter mounting flange to correct the problem.
The Federal Trade Commission Report ordered that the following instructions be supplied as an update to all previously printed owners manuals:
- Apply thin film of engine oil to the filter gasket (Do not use grease).
- Screw on filter by hand until filter gasket contacts flange firmly.
- Tighten filter 3/4 turn. Use filter cap wrench US-4496 or equivalent, wrench extension and standard torque wrench.
- Check dipstick for correct oil level.
- Run engine at various speeds for 3-5 minutes.
- Stop engine, use filter cap wrench (center drive socket), extension and torque wrench for final check. Torque must be at least 18 ft. lbs.
- Re-check dipstick for correct oil level. Add oil as needed.
- Start engine and check for proper seal at the oil filter gasket.
Investigations have revealed that oil leakage was contributed to by several factors. Warped oil filter mounting flanges and mounting studs were either off center, cocked or both.
I recommend that the oil filter be tightened "one full turn after initial gasket contact." Laboratory tests have shown that this exceeds the minimum 18 ft. lbs. as recommended by the F.T.C. I also recommend the use of a cap-type wrench.
In addition, if leakage continues after proper installation or if the gasket appears to be "pushed out", then it is likely the oil filter mounting flange needs to be replaced.
Recommended Check/Replace Intervals For Oxygen Sensors
Many vehicle manufacturers do not provide recommended check/replacement intervals for oxygen sensors, because it is hard to predict when an oxygen sensor will fail. OEM oxygen sensor manufacturers, such as Bosch, work hard to ensure that oxygen sensors last as long as possible. The latest designs can last over 100,000 miles under laboratory bench-testing conditions! But out on
the road, sensors are subject to very difficult conditions which can use sensors to fail earlier than they do under laboratory conditions.
Some Bad oxygen sensor Symptoms can be found when the sensor's ceramic element is exposed to certain types of silicone compounds or when an oil-burning engine leads to the sensor becoming oil-fouled. Also, a small amount of poorly refined gasoline can kill an oxygen sensor, as can the use of some over-the-counter fuel additives which are
not "oxygen sensor safe."
These failures can occur either:
- Instantaneously at the time the contaminant contacts the oxygen sensor, causing
a dead (totally nonfunctional) sensor, or 2) gradually over a period of time. Gradual deterioration results in a "slow" sensor which does not react as quickly as it should, thus causing the catalytic converter to perform less
efficiently. This can lead to premature failure of the catalytic converter, which is an expensive item to replace.
Under conditions of gradual deterioration, "slow" sensors eventually become "dead" sensors. "Slow" pre-OBDII oxygen sensors will cause a drop in fuel economy of 10-15% (costing the average driver over $100 per year in extra fuel costs), while also causing excessive exhaust emissions (air pollution). Poor driveability (hesitating or surging) may also result in some cases.
Unfortunately, the bad oxygen sensor symptoms are not always obvious to the vehicle owner, unless the vehicle fails an emissions test, a decline in fuel economy is noticed, or if driveability problems
Furthermore, while a "dead" sensor can be detected by the do-it-yourselfer with a relatively inexpensive digital
volt-ohmmeter, a "slow" sensor can only be diagnosed by a more expensive oscilloscope or scope meter. Thus, the do-it-yourselfer will probably not be able to spot an oxygen sensor problem until it is too late, and the catalytic converter is already well on its way to failure.
As part of a sensible preventive maintenance program, We recommends that either:
- Oxygen Sensors be checked on a lab scope or scope meter by a professional automotive technician at
intervals specified in this catalog, or
- Oxygen Sensors be replaced by the do-it-yourselfer at the intervals specified in this catalog.
- The "check/replace" intervals published in this catalog are not intervals specified by the vehicle manufacturer, but
are instead Bosch recommendations based on our experience and knowledge of oxygen sensor technology.
One-wire and two-wire "unheated" type oxygen sensors should be checked or replaced every 30,000-50,000
miles. These sensors rely solely on hot exhaust gas to heat up to operating temperature, and therefore are
designed to allow a large volume of exhaust gas to make contact with the active ceramic element.
Therefore, sensors are exposed to contamination, especially the "wide-slot" varieties found on Chrysler, Ford, and
General Motors vehicles.
"Heated" type oxygen sensors have a built-in heater which heats the sensors up to operating temperature.
Therefore, much less exhaust gas needs to contact the ceramic element, making these sensors less prone to
"Heated" type sensors can also be located further downstream (closer to the catalytic converter),
which increases their life expectancy by reducing thermal shock. In addition, the latest versions feature improved
ceramic elements which are more resistant to silicone, oil, and lead contamination. "Heated" type oxygen sensors
should be checked or replaced every 60,000-100,000 miles.
From time to time, every filter manufacturer has had a severely over-pressurized filter returned from a customer. Often the deformed filter is the only sign the car owner has that a problem existed in his lube oil system.
It's possible that the damaged filter was not noticed until it was removed during the next scheduled oil change. However, if the pressure was sufficient to blow out the gasket or unroll the lockseam, the car owner may have experienced immediate and costly problems.
A look at how a lube oil system functions will show that oil pressure is created by the oil pump. The upper limit of this pressure is controlled by a pressure regulating valve which is usually an integral part of the pump.
The pump supplies sufficient flow to lubricate the bearings and other moving parts of the engine. This oil must be under pressure if it is to properly separate the highly loaded parts of an engine and prevent excessive wear. The purpose of the regulating valve is to provide this pressure which on most passenger cars is between 40 and 60 PSI.
The regulating valve is made up of a ball or plunger which regulates pressure with the aid of a spring. The spring is calibrated so that the plunger will lift off its seat when the oil pressure reaches the desired amount. Once the valve is open, the pressure remains fairly constant with only small changes occurring as the engine speed varies.
The filter and all other components in the lube system are subjected to the pressure established by the regulating valve. If this pressure is excessive, filter damage may occur. This is the point that many people who are not familiar with lube systems fail to realize.
What can cause the pressure in the system to exceed the regulating valve setting? The answer is that either the valve must be stuck in the closed position or it is sluggish and slow to move to the open position after the engine has started.
Under these conditions the pressure builds up equally on all components in the system until something happens to relieve the pressure. If the regulating valve becomes unstuck, the pressure will return to normal. If it remains stuck, something has to break.
Normal operating pressure causes no permanent deformation of the filter body. When the system pressure reaches 150 PSI due to a faulty regulating valve, most filters become permanently deformed. At this pressure the gasket usually will not blow out and the lockseam will remain sound. If the regulating valve still remains stuck, the pressure will increase further and the gasket between the filter and the base can be blown out.
This will probably cause the loss of all the oil in the system. If the filter has been installed on the tight side, the gasket may not blow out and the lockseam will unwind as the pressure continues to rise. If the customer is alert and shuts the engine off at the first sign of trouble (red light on or reduced oil pressure) he can limit his loss to a tow job, oil change and new filter. If he drives to the nearest garage, he will probably burn up the engine due to lack of oil.
The main point is that the deformed filter is not the cause of this excessive pressure, but is the victim of a faulty regulating valve.
The customer may ask if a filter that is completely plugged could have caused the overpressure conditions in the system. The answer is no. If the regulating valve is functioning properly it will maintain the pressure on the filter at 40 or 60 PSI even if filter is plugged.