Larger rear wheel cylinders??

[rubberneck]

Hey, a lot of the guys in the second gen forum have been talking about putting in the 27mm 1 ton rear wheel cylinders or even better yet the 30mm units out of a chevy 1 ton. All of them appear to be 5 speed guys however, which means they have the dana80. Do you know if this will work on a 92 5 speed truck with the dana 70. If these units wont work, do you know of a larger wheel cylinder that will?? thanks. Phil

 

[Grey Wolf]

I used the larger wheel cylinders and 3" shoes on my sons '90 D250 If you do a search you should find the correct part numbers

 

[cerberusiam]

Did the same on mine. Have your favorite parts supplier provide the wheel cyclinders for a 1 ton in the same year. The MC are the same so shouldn't be a problem.

 

[JLEONARD]

I replaced the originals a couple years ago and they were 1 1/8 I think. They were larger than what was listed so that makes me think I have a 1 ton axle.

I can get the part numbers tonight if you need them.

Jay

 

[Philip]

Something to think about on larger wheel cylinders.



The larger cylinders require more fluid to move them outward. This in turn will cause the rear brakes to apply slower than a setup with smaller cylinders. If you want faster acting rear brakes the smaller cylinders will improve the feel of the rear brakes. They apply braking force higher in the pedal stroke compared to the larger cylinders.



I use the 1" cylinders in my rear brakes. They can overpower the traction my duals can provide on dry pavement. I can lock the rear brakes up at will,empty or loaded. I have almost 40k on this brake job.



Someone that has run his truck all three ways you might ask is Case500D. His 92 W250 he installed 1 1/8th cylinders on his first brake job. His second brake job he went with one of the disk brake conversions. Now he has went back to drums with 1" cylinders. PM him and ask him which setup worked best for him in a working truck.

 

[rubberneck]

PHilip, good point on the larger cylinders vs pedal travel. I will give my dad the two options and let him decide. Greywolf, did the 3" shoes require different drums??. If you guys have the part # for the larger cylinders that would be great. thanks Phil

 

[TKingsbury]

I agree with Phillip. Not only will it slightly affect pedal travel, but it will exert more force on the rear shoes. If you tow heavy all the time it will be ok, but if you are light 90% of the time like me it will be lock-up city. I don't know about you, but I already have too much rear brake.

Travis. .

 

[JLEONARD]

My rears have only locked up in snow... . rain maybe a couple of times.

I drive empty 99% of the time.

Can't compare feel with other size cyls because I always had the large ones.

They seem to work ok to me.

I forgot to get the number last night... I'll get it this weekend sometime.

Jay



edit... I think I have the 2 3/4 inch wide shoes.

 

[Grey Wolf]

rubberneck,



The OEM brake drums work fine with the 3" shoes, naturally they will need to turned first. I also didn't notice any difference in pedal travel, just a vast improvement over the original brakes and cylinders

 

[cerberusiam]

The Raybestos numbers for the cylinders are WC36057 and WC36058. Brake shoes are 314PG. Not sure if this will cross to all Raybestos vendors as I bought all my stuff thru Les Schwab.



Since most of the braking is done on the front I doubt the small difference in cylinder size and the fact the MC can push more fuild as needed will make pedal travel noticeable. It will take less pressure to apply the same braking force so it will be a wash.



Depending on what axle you have under the truck the 3" shoes may not fit. The lighter duty braking systems did not use the 3" so I think there may be issues with them. If you have the heavy rear with the dished drums you will be OK.

 

[TKingsbury]

My rears have only locked up in snow... . rain maybe a couple of times.

I drive empty 99% of the time.

Can't compare feel with other size cyls because I always had the large ones.

They seem to work ok to me.

I forgot to get the number last night... I'll get it this weekend sometime.

Jay



edit... I think I have the 2 3/4 inch wide shoes.

I will admit I don't think my front brakes are 100%, and that is probably what's causing my front/rear imbalance. BUT, do know, there will be a difference in your braking if you upsize the rears. It may be good it may be bad. It will most likely depend on your truck and driving style.

Travis. .

 

[JLEONARD]

Ok I have the part numbers... . alll Wagner numbers.

The cyls are 1 inch...

WAG WC78974 (F78974)

WAG WC78975 (F78975)

Rear shoes are WAG PAB357AR (2 1/2 inch I think)

Master cyl WAG F98896



Rear Drums WAG BD60328 (6200# axle)

 

[rubberneck]

Hey guys, thanks for all the information. We're going to pull everything apart and see what will work today.