Rear brake upgrade
 

Aloha people,

Just converted the rear brakes on my W 250 per the info in the 'stickies'. It works great however, the pedal takes a longer stroke to work. I understand the larger wheel cylinders require more fluid so.... is there a need to upgrade to a one ton master cylinder to fill up the new rear cylinders in one stroke? Or.... should I just adjust the shoes tighter?....Could I have kept the original W 250 cylinders to have that same 'tight' pedal feel? Thanks guys.

Aloha-

Make sure all the air is out and adjust them up correctly.

You gain mechanical advantage by increasing the length of the lever point or in this case the amount of the pedal travel operating the master cylinder. [This is how a hydraulic bottle jack operates.] This also applies the rear brakes at a slightly slower rate and increases the amount of braking applied to the front brakes. I did the 3 inch brake update 30,000 miles ago and retained the original W250 rear wheel cylinders just for this reason. I have had no rear brake lock up problems with the anti lock disconnected and my front calipers and rotors are still wearing at the same old rate as when it had 2-1/2 inch brakes in the rear basically because I have not been engaging the front brakes at a faster/heavier rate.


Yes, check this first!

Thanks Bill, for the record, I used almost 3/4 bottle of the large brake fluid while bleeding it and then I adjusted the shoes after more 'break-in' time and it's rock solid now.

While reading older posts, I have noticed some of us kept the original W 250 cylinders while only upgrading to the 3" shoe. I thought the larger W 350 cylinder was necessary for the upgrade as more pressure was needed for the wider shoe? I did notice the 350 cylinders had a slightly different fitment while mounting them. It may be to accommodate the wider shoe OR it may have just been the brand that I used? It was Raybestos. Anyhow, like I mentioned, after more 'break-in' time and readjusting the shoes tighter, the pedal is rock hard and bites higher. I'm happy with it. [roll]

You used the DODGE 1-ton cylinders, right ??


I have also read of swapping in the GM 1-ton cylinders.

How do the GM 1-ton cylinders compare to the Dodge 1-ton units ??


Which is the better and why ??


Thanks. :)

GM are 1/16" bigger bore.

From the way my STOCK 1 ton Dodge brakes work, I would not want more braking power back there. They already like to lock up on loose surfaces, especially at speeds lower than the ABS will engage.

Bearkiller,

Yes, I used the W 350 cylinders. From what I was told, W 250 has a 1" bore whereas a W 350 has a 1 1/8 bore, not enough difference to necessitate larger master. I have also heard of the GM 1 ton cylinder upgrade on our trucks. Like Dave mentioned, it's pretty solid.

Faith...

https://www.dieseltruckresource.com/...h-t273527.html

Sorry, my bad. I haven't been on the forums in a while. You still rock. Check your message box from years back, if you've kept them that long. You've answered my diesel questions repetitively without frustration and shared an obsession for firearms. [roll] There's still a common interest here and it's all good. That's how we roll. :cool: