Brake Line Tee Question

[DonG]

Hi,
I am working on getting my new Duramax truck set up for towing. I have determined the best brake controller for my application is one that monitors the brake line pressure of the tow vehicle. To accomplish this, I need to insert a one inch brass tee in one of the two brake lines at the master cylinder. It seems simple enough; separate the existing fitting, insert the new tee, reconnect the brake line to the new tee, connect the pressure sensor to the tee.

Two questions: Should I use a pipe thread lube on the threads? And is there some method to minimize the loss of brake fluid, and eliminate any air intrusion?

I know there is lots of experience on the Diesel Page, but I have not seen this discussed.

Thanks, Don

[SoCalDMAX]

I'm no expert, but I have seen this discussed on other boards. A long time ago, the hydraulically activated setups were the best modulated around.

But now, with the ABS and other stuff, the brake controller mfrs don't even want to mess with all of that and don't want the liability. A lot of people have suggested and use the Jordan brake controller. It's electronic, but gets it's signal from a cable attached to the brake pedal. Once properly adjusted (less than a minute), it gives a braking signal to the trailer in direct proportion to how far you step on the brake pedal. It is a digital, electronic, proportional controller that receives direct input from your brakes, but it uses the brake pedal arm rather than the hydraulic system.

I've got it, and it installs and works like a DREAM. Installation time by an owner should be about an hr, a lot less by a pro who's done it before. Only 3 wires (hooks to factory harness), one cable and a few screws. Indicates proper brake connection, error code and current draw to tell you how much power is being applied to the brakes and let you know if there is an open or short.

I used it once, and it was great. If setup for aggressive braking, it can actually stop the truck and trailer quicker than the truck can stop unloaded, provided the trailer is not overloaded. Check out www.jordanbrake.com, great outfit.

Regards, Steve

[DonG]

Thanks for the reply Steve, but when I talked to Jordan he wasn't sure it would work O.K. with my hydraulic brake system without a good wiring diagram, which I do not have. I already have the Prodigy, and it is ONLY made for "electric" brakes.

After these disappointments I felt I had to go to the "in brake line" method. The manufacturer feels there should be NO impact on the ABS system at all once the TEE is installed.

Don

[DmaxMaverick]

I would not recommend using a hydraulic tap system on late model vehicles with ABS on both axles. If you have an older truck with rear ABS only, it's OK to install the sensor or tap line to the non-ABS line. If you do install on an ABS line, the trailer brakes will fail as soon as the ABS is engaged, which is probably when you need the trailer brakes to work at their best. It will also effect the warranty on the ABS system. When the ABS is engaged, the line pressure is pulsed, which drops the line pressure. I don't know who you got your recommendations from, but they must have a really gullible insurance company.

You didn't give any info on your truck, so, being that you posted here, I'll guess that you have a 2001+ 2500HD or 3500. Also, are you saying that your trailer has hydraulic brakes? This info is important if you want a well advised answer.

[TLA]

Further, I believe that bleeding the brakes requires special tools, and a Tech II to remove the codes that will be set (and I think to check the system out). I had someone change some brake lines for me on my '97, bleed it as you or I might bleed a system, and it was never the same until the dealer went through it.

[IndigoDually]

If You tap the line at the master cylinder the ABS should be unaffected. If the ABS pump is downstream from the tap it should not affect the reading of the sender that You are teeing in. I am assuming that's why the tee is getting installed to connect to a line pressure sender for the brake controller. The ABS computer and pump are on the inner fender aren't they or am I confusing this with my other truck?

Can anybody else with more facts confirm or dismiss my line of thought?

John

[DmaxMaverick]

The ABS effects the line pressure from the actuator piston (inside the master cylinder) to the caliper. You can feel this when it actuates. That is the vibration in the pedal. The ABS system effects the system by releasing the pressure and resupplying it with a pump many times a second. This is true of all consumer type vehicles with ABS. A true hydraulic brake system is different, as it uses a constantly pressurized supply and a regulator valve to apply the brakes.

In any case, if you use a hydraulic tap controller, your brakes will not work in a panic situation if the ABS is actuated. The ABS can be disabled, but that would be another issue.

I use an electronic controller (DrawTite Activator II) with my 12K 5'er and it works very well. A Jordan controller would be much better, but I don't have one. I may be switching in the near future. All my previous vehicles had KH hydraulic tap controllers. The trucks with rear ABS had the controller tapped to the front brake line and worked flawlessly. My '01 is the first truck I've had with 4 wheel ABS.

Do what you want. If you do it wrong, the price may be higher than you could imagine. In many states, if not all, it is illegal.

I hate to sound like the spoiler here. Get all the opinions you want. It won't change the facts.

[AbqGeorge]

Don,

On my '89 K1500 I tapped into the hydraulic system and it worked great.

However, I recall that there was a big warning about NOT using a brass tee for the connection. The recommendation was for a steel, cadmium (sp?) plated tee because of materials compatibilty with the cast aluminum master brake cylinder.

As someone else pointed out, tapping into these ABS systems is a pain. In '89 the ABS was only on the rear, but I NEVER could get a firm peddle using any of the usual methods for bleeding the brakes. Finally took it to the dealer where they used a powered pumping system. The mechanic actually let me watch and I couldn't believe the air bubbles that were in there.

Use Jordan Ultima 2020 now and LOVE IT.

[NickLeinonen]

on the topic of brake controllers, does anyone here know or remember what company made a brake controller that picked up the brake control signal from a cable attached to the service brake pedal linkage. i had it bookmarked before but it was on old netscape and i lost it when i changed to IE...

thanks

[DmaxMaverick]

^====

jordanbrake.com

[Idle_Chatter]

I know absolutely nothing about brake controllers, but I do know that the ABS was mounted on the driver's fender under the hood on my '99 6.5TD Tahoe and that it is inside the driver's frame rail just behind the tranny crossmember on my '01 2500HD Dmax.

[NickLeinonen]

DmaxMaverick

thanks....

i read over the post in more detail and i noticed it was in the second post. duh... redface.gif redface.gif redface.gif

[letsgo]

The 2002 owners manual states " you cannot use more than 0.3cc of brake fluid for any othere braking system" otherwise neither braking system will work properly or you could even loose your brakes.

Use the rear brake line if every thing checks out.

GM is puting the liability on the owner of the truck.

the alternate is Jordan or the inertia type

good luck

[ 11-10-2002: Message edited by: letsgo ]

[ 11-11-2002: Message edited by: letsgo ]</p>