M151A2 Rear Wheel Brake Cylinder

[on-to-berlin]

I am about the work on the brakes of my A2. When I took the brakes apart I found the 1" brake cylinders in the rear. Accoring to the parts book there should be 3/4".
However my mutt came directly from the military. So whas this an upgrade? Are the bigger brake cylinders to work better?

[rickf]

No, That was a screw up! There should be 3/4" on the back and 1" on the front so that the fronts have more stopping power and also so the rears do not lock up instantly and bring the rear end around.

[Fil Bonica]

What did you find on the front 3/4 or 1.0 inch?
Before you go any farther make sure what's there.
As was said there should be 1 inch on the front and 3/4,in back.
A mix could be suicidal.

Fil Bonica

[on-to-berlin]

The front brakes also have 1 inch. So I guess I do it by the book and put 1" to the front and 3/4 " to the rear.

I was just confused because the m151 came directly from the military and I thought maybe there is a reason for it. But then they maybe just put in what they had when doing an inspection.

[Fil Bonica]

Good ,
At least there werent 3/4 inch units in the front.
That could really be exciting!
Change out the rears to 3/4 and you are back in business.

Fil Bonica

[rickf]

What you have is basically the same as the older A1 with the same size all around but someone bumped them up to 1" instead of the stock 3/4". That is a lot better than the combo Fil mentioned. If you have ever had to slam your brakes on I am sure you noticed how fast the rears locked up. Of coarse if you are running modern radial all terrain tires the effect will not be as noticeable since the tires will grab much better than the old NDCC's. I had that experience with my A1 when it was all stock with the 3/4" all around and it got interesting quick. I changed to the later A2 setup with the 1" in front and have had no problems since. I even did a couple flat out panic stops just to see how it would react and it was perfect. Fronts locked and rears just barely locked.

[on-to-berlin]

O.K. so generally what is the consens here now? Is it better to have 1" all round or stay with the book and have 1" in front in 3/4" in the back? Now with everything apart I can still change it

[Fil Bonica]

Go by the book.
It works.
Its your life and you can make the decision on how important it is !

Fil Bonica

[rickf]

What he says, 1" in the front and 3/4" in the back.

[m3a1]

Yeah absolutely...go with the book. Don't turn your back on a whole bunch of research and development. If the designer thought there was anything to be gained by such a simple swap, they would have done it.