Teves Mark IV bleed

Digitalchaos

Registered User
Has anyone ever been able to bleed the ABS section of the TM IV w/o the expensive braker box? If so, how did you do it? Can wires be used to complete any of the circuits at the ABS harness to replicate the signal from the braker box, similar to checking for codes from the EEC IV using a jumper wire?

This is in effort to diagnose my weak brake pedal. I have already tried bleeding the system normally several times, but this does not evacuate the air from the ABS section on the Mark IV, and it seems that air in this section can affect normal non-abs operation.

Thanks for any help..
 
I've looked into it over the last couple days and can't find any information about a different way. I'd need to get a look at the tool required to puzzle out something different. From the description of using the tool it sounds like it is just putting the ABS pump into a mode to flush itself but beyond that I can't figure it out.
 
More research.

It looks like it's a pain in the arse and you must use a bi-directional scan tool to run the "auto-purge" process on the unit.

OTC and others make scan tools that can do this. The Teves Mark IV system that these cars have was very common and was in many GM vehicles as well.

You should be able to find a shop that can do it. I know not everyone has a huge number of shops around, but I would think for $50.00 you could get the brake lines bleed with the proper tool. Just make sure all the brake bleeders are easy to open before going down there.
 
I previously located a tool from Thexton, part #133 Teves IV Brake Bleeder. It is apparently called a breakout box. I learned this after going to many independent mechanics and being told it is definately a dealer only tool. Then I approached the dealer and they told me they were unsure if they had one, and it could cost upwards of 100 dollars to bleed.

Unfortunately, I have also had no results attempting to find a way to bypass this tool.
 
Thanks for the update. Guess maybe the tool is needed. I still think there's a way to rig it, but haven't seen a wiring diagram to come up with any ideas.

There are some good tools on that site. Thanks for the link.
 
No problem. I was also thinking a wiring schematic of either the tool or the harness may reveal a circuit which can be jumpered to replicate the effect of the Thexton device.
 
Does the ABS pump run during rear bleed?

From everything I've read, the ABS pump runs during normal bleeding of the rear brakes. I assume that is the reason for the "key on" requirement. I also read on another site that you don't even need to pump the pedal to bleed the rear brakes. Just turn the key on and hold the pedal down, crack the bleed valve and the the fluid will flow out by itself.

If all this is true, why would you need the ABS bleed tool?
 
We're talking about the late model ABS in the SC's, not the early model. That model didn't have a bleed procedure for the ABS valve body.

The Teves Mark IV has a valve body that is seperate from the vacuum assisted master cylinder. There are lines that go DOWN to the valve body. Anytime the hydraulic system is opened, it's possible for air to get into the valve body. Due to how the valves are setup in the block, the air will become trapped if a "purge" procedure isn't done.

This purge procedure consists of using a special harnes that triggers the pump motor to run for 60 seconds, during which time the valves are articulated one by one flushing any air out of the valve body.

My concern with just jumpering things is a guess that the signaling isn't simply high and low. But maybe current driven rather than voltage. Thus jumpering pins wouldn't be sufficient.

And whatever pins might do it don't appear to be labeled. Any diagram I've looked at doesn't label a pin that could drive the solenoids.
 
shop manual

I have a Ford shop manual that covers the late model Teves IV systems. It has a detailed block diagram with wiring harness pinout for each component.

Starting the motor is easy (jumper pin x to ground). The tricky part will be to figure out what signals/timing to use to actuate the valves.

I can try to post scans if you want to give it a shot.

Regards,
Lee
 
Yeah, I have the diagrams as well. But messing with the valves is not something I want to do. Such devices have duty cycles that if you violate could overheat them and damage them. The unit is not repairable and the entire valve body would then need to be replaced.
 
Bringing this one way back from the dead.

Ok, I have better things to spend my money on than a used but marked up brake bleeder and can't find any shop or even dealer that has the right BOB for Teves IV. So rigging up a circuit doesn't sound sound like such a bad idea.

From what I've seen the Thexton tool starts by cycling the pump, after 20 seconds you open the solenoids via a button and 20 seconds after that it's done. Correct? Does anyone have a circuit diagram or datasheet of the Thexton tool? Input? Suggestions?

Thanks.
 
I disassembled the thexton tool once. It uses a microcontroller based circuit design which eliminates learning it's function from circuit inspection. Instead someone would need to hook it up to a oscilloscope during it's operation to log what it is actually doing.

It might be easier to contact thexton and coax them into either building you one, or describing the specification for what it does. Might find a source for the connector while you're at it.
 
I think if you look at the function of the thing and not necessarily how it accomplishes it, you might have an easier time.

I've thought about building one myself based on the bleeding instructions in the Ford factory service manual. I would like to see one of the Rotunda tools in action so that I could know if the valves are held open or cycled rapidly. I don't know if they could be damaged by having voltage applied to them constantly.

If you think about what the device does, it's just opening the valve block and causing the pump to push fluid through, like a power bleeder would on a non-abs car. The only question mark for me is how the valve solenoids should be activated.
 
bmw also used this type of abs, and I can tell you ours is done through a test plan in the GT1 or ISID testers. the valves are cycled not constant opened. pump will run, for set amount of time and then valves switch on-off, pretty trippy to watch it,

no sure how you can rig this up to do it with a jumber box.

so you say you went to ford and they said they didnt have the tool? I bet there was a test plan in the WDS or star tester. they just didnt wana tell you, if you are positive that you have air in there and you made a repair, maybee paying them to bleed it wouldnt be so bad. Rember there are things engineered into cars that the average, or semi-pro do it yourselfer were never ment to do themselves. you got to weigh that against the price when a repair needs to be completed.

a hundred bucks doesnt sound so bad if the results work and you have good brakes again.
 
I don't have air in the system, I'm just looking at budget alternatives in flushing the system besides the bleed - slam brakes in wet parking lot -bleed - repeat method I've done in the past which tends to be pretty time and fluid consuming(and frustrating). I only asked a few nearby Ford dealers so I'm sure there's one out there that can do it or like you said coax them into doing digging through their testers, but I'm stubborn and plenty certified to DIY:D

The solenoid operation was the main thing that had me curious, I've read/heard conflicting statements about them being held or pulsed. I figured the latter for the possibility of smoking them as mentioned in this thread

If you think about what the device does, it's just opening the valve block and causing the pump to push fluid through, like a power bleeder would on a non-abs car. The only question mark for me is how the valve solenoids should be activated.

Yup that's what got me thinking that I could maybe build a simple breadboard circuit. There's usually datasheets available for microcontrollers, maybe that could shed some more light on this.
 
I bought the unit that connects to the breakout box to do this job. We spent hours bleeding my buddies car and brought it in to do it every day for a few minutes each day for several weeks. Then about once a week we did it for about 3 months. It is ok now but the brakes remained spongey and the light on for a while.
Alan
 
thexton

its funny i have a bleeding unit never used not sure how..will sell if any one needs one.
 

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the valves are actuated, not held open. The purpose is to dislodge any bubbles that might stick to the surfaces of the ports via surface tension. The system is supposed to run the pump while actuating the solenoids rapidly.

If you don't loose brake fluid, i.e. you are just bleeding them to bleed them. It isn't likely to be is any air in the ABS module. The fluid paths are such that brake fluid flow through the module is not a primary path.
 
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