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Question - 1 Ton - Stepped Bore Wheel Cylinders


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The 48 1 Ton used a stepped bore 1 1/4 x 1 3/8 wheel cylinder,

I think if I remember correctly, the larger bore is to the front on all wheels.

 

I found some 1 3/8 x 1 3/8 that have the correct mounting holes and flare fitting.

CAN these be used? What is the design theory behind the stepped bore?

 

 

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If you place any faith in a factory repair manual this read may be for you...if however you do not buy into the idea the engineers of the times had anything on the ball disregard and draw your own conclusions.

 

 

And yes lifted from the internet...and NO I have no clue the book but thinking it was Ford of the era using the Lockheed braking system.

 

 

IMG_0666 (2).JPG

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Pretty sure I replaced my step bores with 1.25 straight bore that was offered from DCM.

The larger bore would be to the front and offer more braking power to that shoe.

At this point in time, Mopar had the best and most sophisticated braking system at the time.

The step bores was just a part of it. As @Plymouthy Adams stated above, could be military that first invented the step bores.

 

Your truck will not blow up because it does not have step bore wheel cylinders.

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I thought it might have something to do with pressure,

I guess they wanted the front shoe to do more of the work.

 

I am not an engineer and do not play one on TV,

best stick to what was stock!

 

 

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2 minutes ago, Los_Control said:

Your truck will not blow up because it does not have step bore wheel cylinders.

 

That is also a good point!

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Today we have much better braking technology .... nothing wrong with keeping it stock.

 

Sometimes we get to the point that step bores are not available, drums are not available, shoes are costly  ... you just need to decide what you want.

 

Factory or something that works.

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Just now, wallytoo said:

as far as engineering goes, stepped bores went the way of left threaded lugnuts, it wasn’t needed.

 

But what about the DoDo bird ... Earth never been the same once they disappeared. Was this time period people started driving Fords with bad brakes. 

 

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33 minutes ago, wallytoo said:

i switched to non-stepped bores in the 1.5-ton.  zero problems.

 

That's good to know and I'm guessing, obviously you went with the larger of the two bores straight across, 

No problems, but did you notice any Improvement or did everything act and feel the same?

Edited by billrigsby
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1 minute ago, wallytoo said:

it’s a 14000 lb gvw vehicle.  any difference has been too minor to notice.

 

Okay, that makes sense but no problems is a plus maybe I'll go this route got plenty of time to think about it. Thanks

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According to my shop manual the large piston goes to the rear. I believe this is because the front shoe would be somewhat self energizing whereas the rear one wouldn’t be. So the larger piston would offer more force on the rear shoe to compensate. 

 

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2 minutes ago, Merle Coggins said:

According to my shop manual the large piston goes to the rear. I believe this is because the front shoe would be somewhat self energizing whereas the rear one wouldn’t be. So the larger piston would offer more force on the rear shoe to compensate. 

 

3D6B641A-29EB-4BF1-95C4-A5579DC8DACA.jpeg.3d53955265c29248d945d9cc03b019a9.jpeg

 

Well dang, I never looked at the book I just know how I took them off I guess they were on wrong from the get-go.

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12 hours ago, Los_Control said:

Factory or something that works.

 

Huh....either I misunderstood you or you are making a pretty controversial stand?

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10 hours ago, billrigsby said:

 

Well dang, I never looked at the book I just know how I took them off I guess they were on wrong from the get-go.

must have been the same manner of repair work as the PO....while I have done tons of work on many cars....some of it rote, it is always best to consult the manual during the process on most repair actions...this could be a good lesson as to why

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3 hours ago, wallytoo said:

 

not in these trucks, they didn't.

 

late b-3 series large trucks, and all b-4 series large trucks did away with the stepped bore, yet retained the pinned brakes.

My B4D and B4GA has floating rear brakes shoes the GA has single bore cylinders (I don’t remember the cylinders in the D 😊)

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Edited by Brent B3B
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4 hours ago, ggdad1951 said:

 

Huh....either I misunderstood you or you are making a pretty controversial stand?

"Factory or something that works. "   

Yeah not very clear there. What I really mean was we have options for brakes on these old vehicles. Although more so for the cars & B1B/B1C then a 1 ton & larger trucks.

We have a few options for aftermarket brake parts, hydraulics are usually available, drums can be a challenge, I believe brake shoes are obtainable. 

Would be are choices for "factory"

we have disc brake conversion options. and also rear end swap options. This would fall under "something that works."

 

A 1 ton may be a bit of  a challenge to find brake parts for. I would think  you could find or rebuild the hydraulics. Finding shoes and drums may be the issue. I have never searched for them myself, just know little is available for the smaller trucks and doubt more is available for larger trucks.

 

Myself I would fix the hydraulics if was all that was needed. But if it needed drums and shoes, I might be tempted to pull a rear end swap from a newer model truck or motorhome with a 1 ton axle and dual wheels. I once had a 1962 dodge 1 ton dually with a straight axle. Would be a perfect candidate if the brake parts are available. May need to go newer yet though. Besides fixing brake issues also fixing modern wheels, bearings, seals, u-joints everything readily available.

But that is just what I would do when my B1B needs rear drums.

 

Sounds a little severe for fixing brakes, but could fix a lot of issues .... If you are not trying to restore something to original.

Otherwise it turns into a search for needed original parts.

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16 hours ago, Merle Coggins said:

According to my shop manual the large piston goes to the rear. 

 

 

Well, you are correct.

 

Once again I've done it open mouth insert foot, I should know to not do things by memory.

 

Not only is the large bore to the rear, the ones on my truck are also marked L and R.

Installed correctly, although they are pretty much shot for the most part.

 

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I'm glad someone piped up to set the record straight on the larger bore going to the rear.  That's how they are on my '49 Power Wagon and I can't imagine them being any different on other trucks. 

 

As for not being needed, I would disagree.  I doubt the factory added this expense vs. a non-stepped bore without good reason.  As someone mentioned, the reason the larger bore is in the rear is because these brake shoes are hard-pinned, and the rear shoes cannot self-energize the way more modern drum brakes do.  The original style 1-ton Power Wagon had this type of brake system through the end of its production run in the late 60's (actually into the 70's for export).

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  • 4 weeks later...

 

After round and round finally got a new stepped bore cylinder.

 

Also ended up with a set of straight bore (1 3/8) cylinders, may use them on the rear.

 

It is a long story, but a messed up EBay purchase and a PayPal refund made everything free.

 

 

 

 

Edited by billrigsby
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54 minutes ago, billrigsby said:

 

After round and round finally got a new stepped bore cylinder.

 

Also ended up with a set of straight bore (1 3/8) cylinders, may use them on the rear.

 

It is a long story, but a messed up EBay purchase and a PayPal refund made everything free.

 

 

 

 

Were the wheel cylinders NOS or new production?  Do you have a link, or was it a random eBay purchase?

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