I had my car towed to a local dealer to bled the brakes after I replaced the BPMV. They called me the next day and told me that they had bad news for me. Seems like now the one that I replaced is leaking and my tranny seal is leaking. I had no fluid in the garage before I had it towed to the shop.

So, today I'm going to have it towed back home. My question is would it be possible for the pump to leak? The only way I could think of if the brake lines were crossthreaded. I know I was very careful not to do that. I worked in the auto industry and installed ABS systems.

I'm going to send the pump back to the place I brought it from. Need to find someone on the forum that has one for sale with the JL4 option on a 2000 coupe. The EBCM has ABS-5/AH/TCS. Anyway I was told it would cost me almost 4500.00 to repair the car.

 

It is a high pressure hydralic pump so of course it can leak,send it back and find out!

 

Yes it's possible, but I would check it out myself first.

Try bleeding your brakes yourself to determine if you have a leak.
In most cases, you don't have to use a dealer's Tech II tool to get a thorough system bleed.

 

This spring I got a good deal on a new BPMV (same one you need) from a forum member. The local Chevy dealer quoted about $235 to replace it. I ended up paying a local Corvette shop about $175 to do it. The Dealer will really get you for the pump itself. Hopefully when you get it back home you will have a better idea on what’s going on. Yes thay can leak but I think it would be rare. Was the pump new? Yes, you do need a Tech II to bleed the pump.

 

I'll throw in a tidbit on needing the Tech 2 to force the BPMV to turn on, you might be able to get around this by faking things out. Simply spin the wheels which will tell the active handling to activate which in turn will turn on the BPMV. It will force it to run which will hopefully bleed it for you or whatever it does. It took care of my issue after I had it out for a few days, air in the lines and so on, the leftovers after formal bleeding, the brakes were still spongy till I did this.

 

Where do ya live ? Maybe some forum member could help you but it's hard to tell since you didn't fill out your profile.

 

Thats the first I have heard of that....sounds like a slick bypass for having to locate a Tech II.

So your car needs to be running I assume and you have it on jackstands....then you just spin the hub by hand with the bleeder cracked open?

I have never quite had the same brake pedal solidness after switching over to aftermarket brakes....I always attributed this to a slight amount of trapped air in that unit (don't have a Tech II obviously).

Please confirm if the method I have above is how you had success

Thanks,
Tony

 

 

Well Tony, if you ever need a Tech2 drop me a PM and I'll send it your way.

Tony

 

I'm just talking outa my *** now, but I would think that a lot of things would have to "add up" to the computer before it starts applying the brakes. If the vss is showing zero (no driveshaft motion), but one of the front wheels is turning a few mph...can't see anything much happening. Besides, if this did work, you'd have to pull the caliper off and block it up so it wouldn't screw with ur wheel spinnin...

 

Thats a real kind offer....much appreciated.

If I ever get this new motor finished and installed I may just take you up on it. In the mean time I will pull out some and wait for the answer to how much "fooling" does the computer really need....LOL

It did sound a bit too good to be true

-Tony

 

The only other trick I know is to go out and stomp on the brakes to open up the BMPV valve and then re-bleed the brakes.

That's what I use to do until I got the Tech2.

 

I had the top end down on my '99 which required the removal of the BPMV. It resulted in air in it. Once all back together, of course I bled the brakes all the way around but they were still spongy in a major way. Re-bled a second time and still the same thing. Knowing that I needed a Tech 2 and didn't have one and the nearest dealer was far away, I elected to drive it through some wet pavement and hit the gas. Of course the active handling kicked in and all of a sudden, I had a lot more brakes. Did it a couple more times and the brakes were nice and solid. It never did go to the dealer for the Tech 2 in this matter and the brakes were fine. Is it a proper way, probably not. Did it work for me, it sure did.

 

I wonder where the air went?

 

No clue, but I had nice solid brakes following that and they haven't been off since. I was wondering the same thing myself at the time thinking that possibly there's a auto-bleed port built into the bpmv somehow. Truly I have no idea but if you wish to activate the bpmv, spin the wheels with the active handling engaged and it'll turn on.

 

Nice trick to remember!

 

Ill be the first to tell ya that Im no BPMV expert but,,,I examined the BPMV functional flow diagram in the service manual and here is what I have observed and believe to be how things work:

The BPMV contains electro solenoid poppet valves. Some are normally open and some are normally shut.

Poppet valves on the BPMV:



EBTCM Electromagnetic coils:





It also contains TWO accumulators that store pressurized fluid and two dampers and a motorized hyd pump.

When the brakes operate normally, the master cylinder supplies pressurize fluid straight to each wheel.

When the EBTCM senses that a wheel is locking up or has no traction, the EBTCM either vents the pressure off those wheels that are locking up Or runs the pump and applies brakes to the wheels that are slipping.

When you get into a situation that requires TC or AH,,you will notice that the pump is always running. That allows the EBTCM to pulsate the correct poppet valves in the BPMV to apply pressure from the pump or vent the pressure in the system to any or all the wheel in fractions of a second. When the pump is running and is not supplying pressure to the brakes, the fluid is being vented to the master cylinder.

If you evacuate the BPMV of fluid while its apart and bleed each wheel of air,,,there is still air trapped in side the hyd passages that are not normally used.
When you cause wheel slippage or loss of traction, the pump runs and forces out the air. Once you have actuated the BPMV pump, most of the air is evacuated out of the BPMV. If you use that method, I recommend bleeding the brakes after to insure that any air left in the normal brake line route is evacuated.

All the TECH II does is run the pump and then it open and closes the poppet valves to purge the air out of the system.

BC

 

Thank You Bill!!! I'm not crazy after all.

 

Very interesting! It would be interesting to know if a wiring harness could be made up to plug into the BPMV and operate it manually while in the garage. That would be a handy tool to have! If I had a spare valve block laying around, I'd definitely experiment a little...

 

I haven't taken the BPMV off yet. I've found another one that I'm waiting for. I do have some brakes on the car now. Hopefully the other pump will get here Monday or Tuesday. I did notice I was able to clear all codes except for C1288. Thanks for all the info. I'll give it a try and see what happens.