Wheel cylinder bore size question

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gliderider06

gliderider06

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I was going to buy new rear wheel cylinders, for rear brakes, on my 87 Ramcharger. Rockauto has 2 different bore sizes available for my brakes. 7/8 & 1-1/16. What's the difference? Does one give more braking power over the other? Confused on which set to get.
Thanks Paul
 
Does your Ramcharger have 11 x 2 1/2" brakes ? Most did and that would take a 15/16" bore cylinder Raybestos # WC37235 (same left and right) : You want the correct bore because that will change the braking characteristics a lot . The vehicle was designed to work with a certain area of friction material , a certain wheel cylinder size , certain hardware - it's like having a cam in the engine working with the correct intake,carb, etc,,,,
 
My Ramcharger has 12x3 rear brakes. Rockauto had both wheel cylinders listed for the 12x3 brakes. That's what confused me and i didn't complete the order until I find out.
Thanks Paul
 
larger bore = more stopping power and more pedal travel.

Do you have power brakes ? If so I would go with smaller bore 7/8
 
Hmmm.... I was selling Dodges in 87 and cannot remember if manual brakes were available.. probably were... I wish I had kept some Data books !
 
I do have power brakes. I'm not sure if they had manual brakes on Ramchargers. I think they were all power brakes.
 
That's a 3/16 difference.
 
gliderider06 said:
I do have power brakes. I'm not sure if they had manual brakes on Ramchargers. I think they were all power brakes.
Click to expand...

as recent as 87 seems to some of us...lol. You would be surprised at how many things were options then. Those Data books were big ! You could still order almost anything ! We were still ordering slant 6 , 4 sp , rubber mat , vinyl seat base trucks... Radio and heater deletes were still available. Steel wheels with poverty caps were common.
 
Did some more digging... 7/8 Is for 12x2.5 and 1-1/16 Is for 12 x 3"
 
gliderider06 said:
Did some more digging... 7/8 Is for 12x2.5 and 1-1/16 Is for 12 x 3"
Click to expand...

Interesting that the more powerful one is used with the larger surface area drum...
might have been a 360 vs /6 or towing package decision.
I believe there were different GVWs as well for AW150s... but all were 1/2 tons.
 
Does your truck have that big brake on a 9 1/4 half ton rear end? Usually the 12 x 3 brake is on one ton trucks with the Dana 60/70 type rear end. Either way use the bigger wheel cylinder
 
Just for reference I use 7/8 with manual brakes. Easier to push pedal, more peddle travel. (AKA poor mans power brakes)

I'd use larger than 7/8
 
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