Booster pin to master cylinder

[Tja1161]

Hello

Looking for some guidance as to what length the booster pin should be on a power brake application for 1983 K5. I am converting back to power from hydroboost and the pin is too long. The new power booster and m/c did not come with a pin. Not sure if they are various sizes as I can't find any OEM listing for them. Here is a reference link (not a C10 but this is idea) https://techtalk.mpbrakes.com/how-t...forget-the-booster-pin-to-master-cylinder-gap

Let me know if you know where I can buy.
Thanks is advance for your help.

 

[1987 GMC Jimmy]

Ugh, I’m pretty sure I threw one away the other day when I was cleaning that would have been exactly what you needed. Although, I’m thinking my booster came with a new one, IIRC. It’s an AC Delco from RockAuto. I don’t know of where to get the pin except going to the junkyard and grabbing one. If someone has the length, they are available online. Or maybe they can just send you one.

 

[chengny]

Hello

Looking for some guidance as to what length the booster pin should be on a power brake application for 1983 K5. I am converting back to power from hydroboost and the pin is too long. The new power booster and m/c did not come with a pin. Not sure if they are various sizes as I can't find any OEM listing for them. Here is a reference link (not a C10 but this is idea) https://techtalk.mpbrakes.com/how-t...forget-the-booster-pin-to-master-cylinder-gap

Let me know if you know where I can buy.
Thanks is advance for your help.

Yep, I've heard this before - the push rod used with hydroboost applications is about an inch too long to use with vacuum diaphragm boosters. Without knowing the rating of your brake system, I couldn't say with any degree of certainty which rod you require. The list of rods is long - and I couldn't even find one for anything but JB 1 & 3 brakes.

GM sells an adjustable MC input push rod to accommodate modified installations. It might be the way to go:

https://www.ebay.com/itm/GENUINE-AC...151420?hash=item4b0195f2bc:g:vucAAOSwq7JT9OS6

To get it correctly adjusted might take a couple of attempts, but it should work. And the price is right - less than $6 with free shipping.

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[Tja1161]

Thank you very much. I knew someone here would have an idea. I will buy that as the price is so cheap.

BTW: how would I know JB1, JB3 etc? It was a 6.2L originally

 

[chengny]

Thank you very much. I knew someone here would have an idea. I will buy that as the price is so cheap.

BTW: how would I know JB1, JB3 etc? It was a 6.2L originally

You won't have JB brakes. The braking systems supplied with diesel powered trucks are classed as JD*.

In 1983 only two ratings were used, either JD3 or JD5. Determine which rating you have by the size of the rear drums (the size of the front discs were the same for either rating). The drums should be 11.0 X 2.00 or 11.15 X 2.75 - see below:

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