SIII and brakes/overdrive upgrades


Hello team,
I've been gone a while but I'm back to my 1973 SIII. The goal for this winter is to get an overdrive installed. Any suggestions as which company? Also, I realized that I don't drive it much because I don't like how everyone expects me to stop as fast as they do on the roads. Is there a way to install power brakes for safety? So I don't rear end anyone?
I've been working out how to set up a bed in there - difficult as it's an 88 and I'm 5'8. I have a few ideas. If you've done something that works, can you post photos? Thanks,


El Matador

New member
Hey bud!

Roamerdrive makes the best OD in the market hands down.

Also, as for brakes, Forbyn Bros. is the place to call. I have their discs on the S3 and they’re ridiculously well made.

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Active member
A series 3 should have power brakes. If they are bad you should fix them.
True! The reason I went with a 71 (late IIa) for my first truck was to have all the “fancy” features of the series III but the metal dash and grille of the early trucks.

Power brakes, back up lights, seat belts (that I replaced anyway) ash tray (that was an option!)

So even if you go to discs, or 109 twin cylinder fronts, you need the booster working!

LR Max

Local Oaf
X whatever for Roamerdrive. I complained the entire time I was paying them, and it has turned into a great investment. In my part of the US, I have to use interstates and I need to AT LEAST do 60 mph. I can do it nicely with the Roamerdrive.

But be careful. If your engine isn't in good shape, you won't get the most out of your overdrive. You still need a good engine to pull the extra gear.

Do you have single circuit or dual circuit brakes? I would upgrade to dual circuit with brake booster to start. I would NOT recommend 109 dual slave cylinder front brakes. Yes they do work better... but the complication and cost isn't worth it. Put that money into a disc brake kit.

On top of that, if you have single circuit, look into doing an upgrade with an early 110 brake booster. Apparently they are an improvement over the old style. However you'll have to do a bit of modification, etc to make it fit. But if you are in there going from single to dual circuit, you've already got a bunch of crap torn apart already so might as well go for the gold.

Also apparently the Santana brake booster is a good upgrade. That said, I can't find a part number nor availability ANYWHERE so its a moot point really. But just in case someone has it out there and willing to share, that would be great.


Active member
Series III is a dial circuit system. Started in 1969 on the “bug eye “

Unless it was downgraded by a prior owner.