Teves Mark IV bleed

My thoughts about building my own came when I was looking at the possibility of having to completely remove the valve block from the car.

There is the good 'ol "drive it to a gravel parking lot and force the ABS system to engage a bunch of times" technique, which I've never seen done, but have heard works.
 
I have have spent a lot of time studying this system and have concluded that the system can be bled without the special tool. I don't have my notes with me at the moment so I can't be specific right now. The only snag that I can see is the pump is a positive placement pump, you can't dead head the pump or you will damage it. The valves seem to be identical except for a slight resistance difference through the control coil. Since some of the valves are designed to be energized except during a abs event, than I believe constant voltage to the valves will not damage them. When I get home from work I will explain with more details when I have access to my notes

Mark
 
Thanks man! I was just thinking of picking up a cheap ABS valve body from a wrecker to experiment with.
 
I have been studying the Teves MKIV anti-lock braking system for our Thunderbirds. I believe I have figured out how to bleed air from the hydraulic control unit without using any special tools. I have studied the wiring harness connector along with a teves repair manual I found on a BMW forum. A special thanks to Mike8675309 cause without his leg work I don’t believe I could have found all the information I needed.
The ABS system is pretty simple in design. There are 8 valves in the hydraulic control unit (2 for each wheel) that open and close to control hydraulic pressure to the wheel cylinders. For each wheel there is an inlet valve and an outlet valve. During normal braking, the inlet valves allow fluid pressure to reach the wheel cylinders and will remain open as long as the system is passive (no ABS needed). The outlet valves bleed off pressure from the lines and will remain closed while the system is passive. At each wheel is a toothed wheel and a magnetic switch. When the wheels are turning the magnetic switches send pulses to the Control Unit which is interpreted as wheel speed, using the time between pulses (pulse width). As the wheel slows down the time between the pulses gets longer. The CU uses this information as well as inputs from other sensors to determine if ABS is needed.
If ABS is needed, the outlet valve open to bleed fluid pressure back to the brake fluid reservoir until the CM determines the wheel is rotating. To maintain hydraulic pressure in the system while the inlet/outlet valves are opening and closing, the CM will turn on a hydraulic pump that is part of the HCU. Near the pump is a small transformer (pump sensor) that will send voltage to the CU when the pump is rotating. By using pressure reduction, the ABS control module can control wheel lock-up.
With most ECM’s voltage spikes are silent killers to electronic components and so they are designed to control ground. The control unit can turn on and turn off components by applying ground to one side of the component (load). The voltage on the component is always there. The teves MKIV brake control module works the same way.
In one of Mike’s earlier post, he was concerned about varying current to the control valve and exceeding the valves load limit. Mike I apologize if I miss-quoted you, I couldn’t find your post to refer too. This is a valid concerned but does not apply here. Because the voltage is constant to the coil, and the CU only applies ground, current remains constant. (I=E/R) Either the valves are open or they are closed. No in-between. Knowing what the valves do, grounds are applied differently between the valves. When the system is passive, grounds are applied to the outlet valves to keep them closed. The outlet valves will fail close upon loss of power. The inlet valves have no grounds applied and thus will remain un-phased on loss of power. They will also fail open. During an ABS event the grounds are reversed, grounds are applied to the inlet valves allowing the coils to energize and the valves are closed. Grounds are removed from the outlet valves allowing spring pressure to open the valve.
Knowing that the valves are nearly identical in construction and operate basically the same way, voltage can be applied nearly indefinitely to the coils without damage. There is slightly higher resistance on the inlet coil, 6-8 ohms vs. 3-5 ohms on the outlet.

There were questions that I had to answer before I felt comfortable with bleeding the system without the special tool.

1. Current and voltage to the control valves: I felt that the control module module may contol voltage and/or current to the control valves but the teaves operation manual clearly states the voltage to the control valves is 12VDC and the control module control the valves by applying ground. Since the voltage is constant, current is controlled by the load (valve) and not the control module.

2. A positive displacement pump will be damaged if it dead-heads. Not much information on the pump but I feel 99.9% sure its a positive displacement pump. That means that when bleeding at least one recirculate valve must be open to prevent pump damage if the pump is on for more than 20 seconds. I would avoid using the bleed screw except to bleed the individual wheel lines and would still have one recirc valve open when bleeding lines.




To bleed the HCU, the pump needs to run to circulate brake fluid from the HCU back to the reservoir with the outlet valves opened and the inlet valves closed. Refer to these illustrations:
module.gif


module2.gif



If I can remember right, the pump needs to run for 20 seconds with the valves closed so the pump can build up pressure. Next, the pump needs to run 20 seconds (?) with the outlet valves open to push air bubbles to the reservoir. Repeat until no air bubbles in the reservoir.

Disconnect the wire harness from the brake control module.
Close the inlet valves. Apply ground by shorting pins 1, 20,38,54,55.
The outlet valves should already be closed.
To start the pump, disconnect the wire harness from the brake control module. Turn the ignition on. Apply ground to the main and pump relay by shorting pins 1, 15, and 34. This should energize the relay and the pump should start. Run for 20 seconds.
Stop the pump by removing ground from pin 15 and 34.
Open the outlet valves by applying ground (pin 1) to pins 2, 21,36, and 18.

You can manipulate any valve you want by applying the grounds to the right pins.

You can view the Teaves operation manual here
 
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thanks for all of that information and the clarifications. pretty cool you were able to figure all that out. Get a connector plug for that and it would be pretty easy to rig up a tool to make it easier to ground the various connections.
 
The "redneck" way to bleed the Teves IV is by going out on an empty road/street and slamming on the brakes to activate the antilock system. I'm told by my mechanic that you'll need to redo this several times. (bleed, then activate, bleed again, then activate) You can find the Ford bleeding unit that plugs into the antilock control module. I bought one on the internet about a year or so ago when I had to replace my antilock valve body that was all corroded and causing a antilock light. The Thexton unit is another unit like the Ford unit, but Thexton doesn't make it anymore.

The Ford unit is called an Anti-Lock Brake adaptor - tool number T90P-50-ALA. Sometimes you can find them on Ebay. I bought mine from a website that I found on SCCOA. (see link http://www.sccoa.com/forums/showthread.php?t=109145

Website to possibly buy the unit from is http://rcmautomotive.com/id26.html It cost about $100.00. You'll have to email them to see if they currently have any more.

Good luck.
 
Thanks mkbrower! Awesome findings, I'll definitely try this out in the next few weeks, I have a spare ABS control unit I can hack the connector off of, I could even rig up a nice circuit chalk full of switches and LED's just for the hell of it:D


I've done it the redneck way twice on this car, I would go through about 5 quarts until the fluid was mostly clear.
 
You can bleed the system from the pig tails of the control valve and motor if you are looking for an alternative way. Today I verified that the valves and pump would run to bleed the system by using jumpers right at the pig tails. I didn't want to run the pump dry for more than about 20 seconds, and verified all outlet valves operated. I have no doubts that the brake system can be bled using jumpers here. The jumpers were easy to make using 18g wire and splices squeezed to slip tightly over the pins. The pump pigtail is female so the wire slips into the holes.

As I said in a earlier post, the inlet valves are nomally open and fail open with loss of power and need to be open to bleed the Hydraulic control unit. DO NOT apply grounds to any of the inlet valves as the valves will close off if the coils are energized.

Run 12VDC to pins 1 and 16 and to the red wire on the pump pigtail. (refer to the pictures)


According to the service manual, to bleed the HCU run the pump for 20 seconds to build pressure and then open all the outlet valves for another 20 seconds by applying grounds to pins 3, 9, 13, 15. After 20 seconds close the outlet valves and run the pump for an additional 20 seconds. Repeat if needed. To further explain, the pump should be running continuously for a full 60 second time line. Open the outlet valves at the 20 second mark on the time line and close the outlet valves at the 40 second mark on the timeline.

ABS1.jpg


ABS2.jpg


ABS3.jpg


ABS4.jpg


absvalve1.jpg


absvalve2.jpg


Mark
 
So the process would be...

-Bleed/flush main brake circuit like normal
-Run the pump 20 seconds
-open(ground circuit) outlets for 20 seconds
-close(open circuit) outlets for 20 seconds
-Bleed main brake circuit like normal again
-Done?

My only questions being earlier in your other post you mentioned closing the inlet valves a few times which seems to contradict your last statement about not opening them at all? Am I missing a step or two or ten or am I just reading it wrong?

Also (I should have mentioned) is there any additional tricks needed to bleed solenoids for traction control units like mine? My EVTM shows SV1(inlet) and SV2(outlet) as additional solenoid controls at pins 37 and 40 on the CU connector, I assume the same jumpering method applies to these like the other ones but just want to make sure.

Thanks again for the help, your knowledge has been invaluable!
 
I'm sorry about the confusion. I typed it backwards in my first post. The inlet valves must be open to allow brake fluid to flow to the wheel calibers and back to the outlet valves ultimately back to the brake fluid reservoir.

My brake system is completely disassembled so that I can replace all the brake lines and restore the individual componets. When I am ready to refill my brake system, I will use a hand vacuume pump at each caliber bleed screw to draw brake fluid from the reservoir into the lines. I will use gravity to fill the lines going from the reservoir to the outlet valves at the HCU.

When all the lines are full of fluid I will bleed the ABS HCU using the procedures I described in the second post. Next, I would bleed the brake lines as I would a non-ABS car; RH Rear, LH Front, LH Rear, and RH Front.

Mark
 
bump bump 7 years later

i just acquired my #9 a purple 95 auto, it came from up north and the brakes lines were rusty so i went ahead and fabbed all new rear lines

now i need to be bleed them hence

got all out i could the conventional way yet the pedal still goes to the floor, guess i'll give this approach a shot and post back with my results
 
mkbrower is spot on

Mark,

Just wanted to add that I took and followed your instructions for a home made bleeding system for Teaves IV on my 95 SC 5Speed. Needless to say that once I got all the pig tail wires fabricated, the pump ran as detailed and the outlet valves came on to finally allow the air to escape the system that has plagued me for years. Awesome.

v/r glenn

:cool:
 
will try to post pictures of the fabircated wires and pig tail connectors later. Like Mark says, 12VDC and Ground to the ABS motor from the bottom of the left front fender, and open the connector in front of the battery compartment to put 12VDC to pins 1 and 16, and ground for 3,9,13, and 15 and here them go click click when power is applied.

v/r grh
 
You can view the Teaves operation manual here

Does anyone have this PDF they can send me, or the wiring diagram for the teves unit? My sisters master cylinder had to be replaced, and now they cant find a shop that has the tool to bleed the system properly. If I have the wiring diagram I am confident I can get it sorted out. Havent looked at the car yet, doing my research first. Thanks!
 
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