[Benchai]

This is a project I've recently completed, and with the help of alot of you guys I avoided many pitfalls. I still found some though, so I thought I'd post up my little journey and maybe it'll help someone else in the future

You'll need a booster and master cylinder of matching models, and a pedal box to suit. Also the brake lines from the master cylinder to the bracket on the guard and templates for the holes. I used a hole saw for the big hole, and it was just a cheapy multiple blade thing from the hardware. I started by removing everything in the way. I took the intake manifold off not only for access, but it made it easier to remove the plug for the vacuum pipe, which was a real bastard to get out. I got a 90° adapter and 8mm nipple from the local plumbing place.



Next was taking out the pedal box, which necessitated taking out the steering column



I had used one of my son's numerous WT bodies to make a template for the holes



and cut using a hole saw and drill. I covered the old holes with some plate and double sided tape.



The new pedal box went in really well, though it did need a special blend of psychology and extreme violence to line the holes up. Once in place, the column went back in, and the booster was bolted in place. Then bolt up MC and connect the lines. Now the clutch cable. I found that the existing holes lined up with the pedal box, not the top of the clutch pedal, and some measurements confirmed that I had to relocate the hole upwards. Aren't Nutserts the best



With the clutch cable entering the firewall at the right place, and matching booster and master cylinder I can say that it's really worth the effort. All I have to do to finish off is solder the matching plug to the wiring harness to connect the warning light, put a blanking grommet in the old clutch cable hole and remount the heater tap.

[mrw82]

Nice work. Does it make much difference to the brake performance/pedal feel?

[Benchai]

Mark, it's a very worthwhile upgrade. I mainly did it because my son has just got his P's and all the cars he will drive will have a responsive brake pedal. It's certainly got that now, though I am still getting used to the change. Engine braking is very effective with the standard gearing but I do like it.

[jimbo_jones]

Awesome write up mate, This is destined for the good tech section.

[Benchai]

Footnote:
I mentioned earlier about matching booster to MC. They changed at '89, and post and pre 89 don't match up. There's a difference in the length of the shaft in the booster and if you mismatch parts either the MC won't sit home, or there is a couple of inches of no pedal before the MC begins to be activated. Post '89 is a better option if you're running standard airbox as these are smaller and allow the airbox to fit with clearance. The easy way to tell is that the post 89 MC resevior is held in place with a split pin and the pre 89 uses a screw. Also the low level float is in the resevoir in the later model whereas it's in the lid in the earlier ones. Bloody hell it's a massive improvement, well worth the exercise. If I knew what I was doing and didn't take a couple of wrong turns it would have only cost around the $200 mark.

[sogone]

Yay for Benchai.

Question. I have a pedal box and brake booster/MC/resovoir from a WT 94 sitting around and a 10/84 1 liter with disc brake front end. Will these parts be all I need to make it awesome as you described? There's just a bit of jumping in your description to different parts and stuff.

[Benchai]

Yep, should fit right in. I found when I used my son's 88 set for awhile I found the Air Box was a tight fit. Otherwise there's no difference so go for it. You may find that the 84 has the clutch cable entering in the right position for the pedal box too. It's all much easier if you have a body to mark a template off, and if you don't I'm happy to send you an image of mine

[sogone]

Not a bare body. I'll pm you my email? Will that work out better?

[Benchai]

Yes, I don't know how to put attachments on here

[mrw82]

The late 1 litres (+84. With disk brake front) have a different master cylinder to the earlier drum braked model. Not sure if the mounting is the same, so it may infact be easier to mount a booster to then benchais, I don't see any reason why it'd be any harder. Let us know how it goes for you as it might convince me to do it to mine.

[dougies_tx5turbo]

Bump
Old post but has anyone done this to a sj40 84 disk brake sierra and no is it the same ?

[Gwagensteve]

If it has a plastic dash like a narrow track 1.3 then it's much easier. If it has a steel dash it's the same as Benchai's instructions.

[dougies_tx5turbo]

Okay I thought as much. One of the mods I will be doing after I get the sj40 on the road need some extra help pulling up that Almighty 660 turbo...

[Gwagensteve]

You 100% don't need a booster to stop any sierra, least of all a light SWB with a light motor.

[dougies_tx5turbo]

This will be a rainy day mod

[Gwagensteve]

Waste of time. Use the right booster for the brake size and it will stop fine.