New Alternator & Brake Master Cylinder

Well since the web page is bugging me about not posting in several weeks I thought I'd share a couple of pictures of my slow progress.

I've just finished installing the 12si 94amp alternator on the stock bracket. I machined the bracket's inside ears to locate the alternator in the correct position to line up with the stock tension arm. I run the belt on the inner pulley set using a new smaller pulley for the alternator. With the smaller pulley I'm running around 3x crank speed, so I've got good output at idle! You can see in the lower left of the pic that I added a sliding sleeve like the original mount, but it now biases the alternator to the front when the pivot bolt is snugged down. I still need to get a shorter pivot bolt, but the rest of the install is complete. The wiring is pretty straight forward for a 3 wire install. The output is tied to the battery direct, the voltage sense is tied at the battery too, and the excite wire is connected to the ignition switch via the old alternator harness. I did insert a diode in the exciter wiring to insure that the engine won't run on when the key is turned off. I also doubled the capacity of the wire running to the fuse panel, and removed the ammeter. The headlights have been rewired with relays to remove that load from the original wiring harness. (that mod is worth 1 - 1.5volts more at the headlights)

The last couple of pics show my new booster and master cylinder install. I'm working on the new hardline routing now, with only a couple more pieces to form. It was hard to find a clean routing for the residual valve and adjustable proportioning valve. I hope the routing I've done won't have any problems with vibrations. At least I've been able to make double flares without any problems. Since there aren't any NPT to Metric double flare adapters that I can find, I just had to put english flare nuts on one end, and metric on the other. You would think Wilwood or someone would offer metric adapters for their products.

That's my progress for the last few months. By the next time I get the reminder to post something maybe my brakes will be done!

Jeff

Hi All:

Is that a FJ80 brake master cylinder? GM alternator, I assume?

Looks good!

Regards,

Alan

Josie'sLandCruiser said:

Hi All:

Is that a FJ80 brake master cylinder? GM alternator, I assume?

Looks good!

Regards,

Alan

Click to expand...

Alan,

Yup, mid 90's Non Abs Master, with a mid 80's 1 ton PU Booster. The Alternator is a GM 12si, very popular.

Jeff

seen these?

Yeah, looks like a Parker fitting or something similar. I didn't want to run Stainless tube or other seamless tubing. While crimped ferrel type fittings aren't recommended for brake work, I know they are rated for the pressure, but I decided not to use them. The only other alternative I would consider is -AN fittings. In the end I opted for standard Bundy tubing / brake line.

Thanks for showing another alternative.

Jeff

Swage-lok. I had brain fade earlier and couldn't remember. Their suitability has been debated before. They're rated for some 1.5 gazillion psi. I have used them for years after being unsuccessful at double flaring. These are really cool as you simply cut the tubing, slide the unit on and tighten.

Hey Jeffery,

Where are you located in Vancouver? I wouldn't mind picking your brain a little bit. PM me if you wouldn't mind sharing some of your expertise.

Thanks,
Kyle

dgangle said:

Swage-lok. I had brain fade earlier and couldn't remember. Their suitability has been debated before. They're rated for some 1.5 gazillion psi. I have used them for years after being unsuccessful at double flaring. These are really cool as you simply cut the tubing, slide the unit on and tighten.

Click to expand...

I've seen those on a few jets, hydraulics.

very nice, clean too. good work

Jeff, I've been studying your 12si upgrade. Looks very good. What are the specs on the smaller alternator pulley? Was it already installed on the new alternator or did you find it another way?

Thanks for the info

I ordered the smaller pulley from: http://www.alternatorparts.com/Alternator_brackets_2.htm it's part number A203. It fits right on the alternator, but I did increase the counter bore depth to get more thread engagement for the clampdown nut. The only reason I modified the pulley was because I used the stock bracket with minor mods. I had to shim the pulley out about 0.25" for alignment, which took away from the nut engagement. If you change your mounting configuration compared to mine, I'm sure you could use the pulley as is.

Jeff

Jeffery

I am in the middle of doing the alt mod with the 2F bracket and ran into the same spacing problem, mis-aligned by 1/4 inch. What did you use to make the spacer with? I had looked at the A203 pulley you used and wondered if it was the one I needed.

The guy at Truck-N-Tracter Electrical here in Albany that built the alt for me told me that if I had run-on problems to just run the exciter wire to the acc. side of the ignition switch instead of the switched hot side. Haven't got that far yet so I don't know,but I figure it's worth a try.

handcannon said:

Jeffery

I am in the middle of doing the alt mod with the 2F bracket and ran into the same spacing problem, mis-aligned by 1/4 inch. What did you use to make the spacer with? I had looked at the A203 pulley you used and wondered if it was the one I needed.

The guy at Truck-N-Tracter Electrical here in Albany that built the alt for me told me that if I had run-on problems to just run the exciter wire to the acc. side of the ignition switch instead of the switched hot side. Haven't got that far yet so I don't know,but I figure it's worth a try.

Click to expand...

For the spacer, I used two large washers I had around. If I remember correctly, (sorry but I can't currently check as I'm in Singapore on a business trip ), I think they are 5/8 ID. Not certain on the size, but what ever fits the shaft. They fit real well, and added close to the 1/4" I needed. Since the diameter of the spacer is small, I wasn't worrying about any balance issues.

For the Excite wire, I used the stock harness and jumpered the two wires right at the old Voltage Regulator connector. One of the wires is switched, and the other runs out to the Alternator. the jumper I made used two female spade connectors, they pushed right into the existing connector, and put a diode inline with the wire. I actually tried the setup without the diode and it worked fine, no run-on. But to be sure, I added the diode. Any barrel diode of 2+ amps should work well, just make sure the end of the diode with the white ring points to the alternator.

Hope this helps. Let me know if you have any other questions. Good luck!

Jeff