Brake Sender Unit

**Jim** · 05-02-2014, 01:43 PM

All I am trying to sort out my wiring on my ute but have found a problem. I have a single point relay on the brake sender unit but the wiring is for a 2 point. What should a HX have?

Thanks Jim

**SLR_dave** · 06-02-2014, 04:23 AM

Hi Jim, I'm not sure I understand this question.

I think you are describing the electrical connection on the "t piece connector" (by "t piece connector" I mean the piston housing for the dual brake system - which distributes the brake fluid to front and rear brakes, and bolts on to a bracket over the drivers side shock absorber tower)?

**Innuendo** · 06-02-2014, 04:45 AM

It's known as a proportioning valve.
Brake Fail Warning Switch.

**SLR_dave** · 06-02-2014, 04:59 AM

Originally Posted by Innuendo

It's known as a proportioning valve.
Brake Fail Warning Switch.

A much more accurate name yep, but it often slips my mind, 't peice connector' was used by Gregory's in their LH-LX manual.

**Innuendo** · 06-02-2014, 05:18 AM

I can only find a single wire in the wiring diagrams for HQ-Z but I know the two wire version exists. It has a plastic cap with lock.
Not sure when the change happened.

**SLR_dave** · 06-02-2014, 06:18 AM

Yep it's a good question. Has stumped me in the past. Just did some quick web research (haven't got any books at all with me atm).

These links may help for starters.

http://holdenpaedia.oldholden.com/Br...rtioning_Valve - (need to scroll down to bottom of page to see all three entries)

http://www.aussiev8.com.au/members-l...ing-valve.html - (look especially at post #4, it also conflicts with psi numbers on post #1)

But, this is only brief web research, and isn't conclusive, the aussie8forum post #4 lists four valves, and the holdenapeadia site entry only comes up with three, also neither focus on vans. (I realise you have a ute Jim).

For the brakes to work as designed you obviously need the right proportioning valve for your set up, however (and I have wondered this before), many H series in existence today may have had the valve replaced with a spare from a wreckers by a previous owner at any time, and that could have come off Torana or any 70s H series - which may be the issue you face Jim, - (unless, as an alternative, the wiring harness could have been changed/adapted)?

About a decade ago I got handed a "clean" proportioning valve for my HJ wagon from a wrecker who pulled it off a car with good lines for me, but I never knew what it came off! (it passed the brake test at rego so lol.... well, lol with a 'hmmmn um' , attached.)

Knowing what models of proportioning valve were used, and which one for which type of vehicle and brake set up has always been beyond me - I never knew where to get the information. Does anyone happen to know off-hand? Otherwise, maybe this could be a good research thread.

An affirmed and accurate list, (model nos, crack points, vehicle series and brake options) would be a really useful thing.

**HK1837** · 06-02-2014, 07:20 AM

It was an ADR change to the 2 x wire switch. which separated the brake fail indication from the handbrake indication. Changed in HX or late HJ from memory.

**Jim** · 06-02-2014, 08:37 AM

Thanks everyone for the information. I will start looking for one today

**wbute** · 06-02-2014, 09:36 AM

Must have been HX. HX gts dash has brake fail and hand brake warning lights, HJ shares a light and had high beam warning in the other spot.

**Dr Terry** · 06-02-2014, 09:38 AM

AFAIK they used a single pin differential pressure switch for late HG, all HQ & HJ. HX saw the 2 pin switch & this carried thru to HZ & WB.

On the late HG & HQ the switch was mounted in a junction block. There was no proportioning valve on HGs & on HQs the prop valve was mounted along the subframe rail under the driver's seat, on disc braked cars only.

For HJ, HX & HZ the switch was mounted on the proportioning valve. In WB it was mounted on the master cyl which also had the proportioning valve in built.

Dr Terry