Questions about Jacobs brake

[Mike Cureton]

Does the Jacobs brake have a port for the thermocouple for the EGT gauge? If not, what is the best way to mount the thermocouple?



Is there a switch available, to turn the brake off, that mounts on the shifter?



Thanks for your help,

Mike

 

[RustyJC]

Originally posted by Mike Cureton

Does the Jacobs brake have a port for the thermocouple for the EGT gauge?

My 2002-vintage doesn't.

If not, what is the best way to mount the thermocouple?

I mounted mine pre-turbo by drilling and tapping the exhaust manifold.

Is there a switch available, to turn the brake off, that mounts on the shifter?

Yes, I got my switch and bracket at Diesel Injection Service.



Rusty

 

[Mike Cureton]

When you drill/tap the exh manifold, is there a specific place to drill? This may be a dumb question, but did you remove the manifold form the engine prior to? If not, how did you get any metal shavings out?



How expensive is the shifter switch?



Thanks for your help,

Mike

 

[RustyJC]

Originally posted by Mike Cureton

When you drill/tap the exh manifold, is there a specific place to drill?

I did a quick search of the forum and found many threads dealing with this. Here's one that contains a sketch.

This may be a dumb question, but did you remove the manifold form the engine prior to? If not, how did you get any metal shavings out?

Just take your time and pack the flutes of the drill bit and then the tap with grease to catch any cuttings. Clean and repack frequently. After you have the hole drilled and tapped, fish around in the manifold with a flexible extension mechanic's magnet (available at Sears Hardware, among other places). A few leftover small shavings aren't going to hurt anything - they'll blow out through the exhaust side of the turbo as soon as you fire the truck up.

How expensive is the shifter switch?

I don't recall exactly (I bought mine 1-1/2 years ago), but it's not expensive at all. I'd give the guys at DIS a call.



Rusty

 

[JWhitcomb]

The exh. elbow on the Jacobs I put on my truck had two cast in bosses with a center dimple. I drilled and tapped them and installed brass plugs. I would do that even if you are not going to use them. Makes things a lot easier if you do decide to install something down the line. Make sure you use a hi temp anti-seze on the brass.

 

[PBayer]

Mike

I just installed a shifter switch from Pac. Bought it from Piers Diesel. Nice switch. You need a relay to use the switch because the jacobs switch uses 4 wires and Pac uses 3. If you need a diagram e mail me. -- email address removed --.

Paul

 

[JWhitcomb]

You don't need a relay if you just cut into the stock switch circut.

 

[PBayer]

Do you mean the dash switch? I didnt use it. I didnt like where it was to be placed. Just used the shifter switch.

 

[JWhitcomb]

It's been awhile since I installed my brake so a bit fuzzy. I installed the supplied switch on the dash and cut in my shifter switch in the same circut, then went on as normal. Not sure why you would need a relay. Did you hook into the ECM? I figured the dash switch might keep someone from turning on the brake sometime. But I have never let anyone drive my truck yet.

 

[gitchesum]

The factory supplied switch uses four wires. The yellow and red are the only wires needed to activate the brake. The white wire is the power wire for the light on the switch and the green is the ground wire for the light on the switch.



We only passed the yellow and red wires in the cab and wired them to the BD shifter switch. Works like a charm.



This was an install on a 2001.

 

[JWhitcomb]

I was wondering how many people don't use the ECM. I hooked mine up and haven't noticed a need to get rid of the 2 second delay.



I built a shift lever switch mount that can use up to three switches. I use one for the brake and will use the other two for a air horn and driving lights. Anybody have a need for one, I can machine it for your switches or ones like I use.

 

[PBayer]

Hooking up the red and yellow wires to the shifter switch does work, but the light on the switch will only light when the e brake in activating. Using the relay allows the light to stay on just as the jacobs supplied switch does.

 

[JWhitcomb]

Got it, thanks.