Front "shocks"

[Freightrain]

Well, it finally happened. The right front "arm" that attaches the axle to the "snubber" gave way. The upper ball joint fell apart allowing the arm to fall and bend itself up. So.....I need to either replace the arm OR retro fit some R model shocks on the front. Not sure how much those old 'shocks' really do? Probably not really an issue anyway, but do need to fix what's broke.

Need to see some pics of R model shocks, how they mounted them, maybe the lengths? I could retrofit/make brackets. Got ALLLLL winter to figure it out

[vanscottbuilders]

Matt Pfahl has the swivel ends that you need, and the rod is just U-bolt stock

with the ends threaded - if you want to go with the original set-up.

Paul Van Scott

[David Smith]

Matt Pfahl has the swivel ends that you need, and the rod is just U-bolt stock

with the ends threaded - if you want to go with the original set-up.

Paul Van Scott

Does anyone have a source for the entire rotary-shock unit? Thanks, David Smith.

[Freightrain]

If I could get std shocks.......I'd glady give you my stuff.

[vanscottbuilders]

I've never had one apart - but from the manual, the older rotary hydraulic

shocks used on the B model appear to be fairly easily rebuildable.

I intend to find out ASAP.

In most cases the rod has failed or an end has broken, and the shock unit is still

on the frame of the old trucks.

I would check with the parts guys like Kevin All at All Mack, or a local vendor

near you. The rotary shocks should be pretty easy to come by.

And, contrary to popular belief, the rotary design is not bad at all. It does the same

job as a tube type shock, but has far fewer options for jounce or rebound, so it

is more fixed in its' intended use.

The biggest failure for the rotary units is leakage, and the failure to refill the shocks.

They don't work at all if they are empty.

Now - for Freightrain -

Fabbing up shock mounts should not be too difficult. The geometry of the front axle

is fixed by the springs and the mounting shims. So as long as the shock doesn't bind at all,

it should be fine. The shock set-up on the later R models probably is as simple as it gets.

You might even try to salvage a set of upper and lower mounts for your use.

Or - even try a front axle from the R model, with the lower mounts already in place.

Experimentation - it's a big part of why we do this!

Paul Van Scott

[David Smith]

I've never had one apart - but from the manual, the older rotary hydraulic

shocks used on the B model appear to be fairly easily rebuildable.

I intend to find out ASAP.

In most cases the rod has failed or an end has broken, and the shock unit is still

on the frame of the old trucks.

I would check with the parts guys like Kevin All at All Mack, or a local vendor

near you. The rotary shocks should be pretty easy to come by.

And, contrary to popular belief, the rotary design is not bad at all. It does the same

job as a tube type shock, but has far fewer options for jounce or rebound, so it

is more fixed in its' intended use.

The biggest failure for the rotary units is leakage, and the failure to refill the shocks.

They don't work at all if they are empty.

Now - for Freightrain -

Fabbing up shock mounts should not be too difficult. The geometry of the front axle

is fixed by the springs and the mounting shims. So as long as the shock doesn't bind at all,

it should be fine. The shock set-up on the later R models probably is as simple as it gets.

You might even try to salvage a set of upper and lower mounts for your use.

Or - even try a front axle from the R model, with the lower mounts already in place.

Experimentation - it's a big part of why we do this!

Paul Van Scott

Mr. Van Scott, great idea on swapping the R-Model axle. The R-Model spring leaves are about 1/2" wider than the ones on the B-Model. If not for that, you could just swap the spring clip spacer with the integral shock mount for the old one. Best regards, David M. Smith.

[David Smith]

Mr. Van Scott, great idea on swapping the R-Model axle. The R-Model spring leaves are about 1/2" wider than the ones on the B-Model. If not for that, you could just swap the spring clip spacer with the integral shock mount for the old one. Best regards, David M. Smith.

Freighttrain, thanks for the offer! I hope you solve your problem. David M. Smith.

[LocomotiveBreath]

I've been doing some measurements of my own and the R600 front axle is about 5" wider overall than the B model front axle.

[vanscottbuilders]

I didn't say changing axles would be easy.

Freightrain is a racer. They can make anything work!

I agree - it's not totally original,

but a little wider axle looks really good on a B model.

Check out Jaime Samuell's B-85. The axle is from a

fairly modern truck, Fr---tlin-r I think. It' sets the wheels

out toward the outer edge of the fender and fills the wheelwells

really nicely. More than that, though, it has modern brakes, Budd hubs

and power steering. Makes the truck much more useable.

Still, I believe that the rotary shocks are a good way to go, in the interest

of economy and originality.

It's nice to have options.

Paul VS

[David Smith]

I have known that the "R" axle was wider than the "B" axle for at least 40 years, yet I didn't think of it until reading LocomotiveBreath's post. "Senior moments" are becoming more frequent every day. I never got farther than the width of the spring leaves. I had wanted to use the "R" shock mounting set-up on my "B". In that case, the u-bolt, or"spring clip", spacer would have been too wide.

[LocomotiveBreath]

Here are a few R model shock mounting pictures for ya. The shock measures about 23" ctr. to ctr. at level ride height. The R model upper spring mounting pad has the cast in lower shock mount and the upper mount bolts to the frame. The R spring is wider but it looks like you could probably just mill some off each side of the R model spring mounting pad to allow its use with the narrower B springs. Hard to say for sure without pulling the mount but it would be an easy mod. if it worked.

Edited October 30, 2008 by LocomotiveBreath

[theakerstwo]

Can you guys still find the shock fluid that goes in the rota shocks? glenn

[Freightrain]

Thanks Loco for the pics.

I'm kind torn between converting and just fixing. If I want to drive it in two weeks, I'm thinking I'll just fix what I have. The rod ends have been sloppy for all the years I've had it, so it was just time til one fell apart. Too bad it was the top one and it bent the rod as it fell and hit the pavement(going down the road).

If I fix it, then likely I'll get new ends from Matt Phal and do it right. No sense in rigging it and then putting std shocks on it. Once the ends are fixed, it should last a lifetime for me. It's not like the front suspension moves much anyway.

I do want to crawl under it and see how well the rotary works. Not even sure if they do?? Maybe this weekend after a trip to the chiro so I can actually bend over and crawl under the truck LOL!!

The wider R model axle is not an option. I don't care for the "wheel stick'n out" routine. In my opinion anyway. I can tell a chassis swap a mile away with a B model as the front wheels just don't fit UNDER the fender far enough in my eyes. Like using an R model bumper....just wayyy too wide. I had my custom bumper made to fit the width of my tires, so it doesn't stick out the sides.

[mackmixer]

Can you guys still find the shock fluid that goes in the rota shocks? glenn

I would bet that the early Ford V8 guys and forum have a source for shock fluid. Those shocks have got to be similar to the Macks, only smaller.

[vanscottbuilders]

The Ford V8 guys are a great idea, or almost any antique vehicle

people for that matter.

I have used light hydraulic fluid, and it seems to work well,

but who knows if it is really right.

Contacting a racing suspension shop might yield good results, too.

They would be building shocks. I would think that the fluid would be

substantially compatible.

I'm going to dig out my manual and research it a little.

Paul VS

[Lmackattack]

I would bet that the early Ford V8 guys and forum have a source for shock fluid. Those shocks have got to be similar to the Macks, only smaller.

I have a mag with a write up in it how to service the old shocks/ I will see If i can find it.I think it had contact numbers to source old parts?

Trent

[Black Bull]

Hey Guys,

I'm in the process of fitting a set of the rotary shocks to our B Model. it never had any on it when we restored it.

Later this month the old girl is doing about a 5000 mile round trip so want to fit a set of shocks

The problem is that using the exisiting holes in the chassis, the geometry seems all stuffed up.

Anybody able to post some pics of how they should mount ?

[Black Bull]

bump

[41chevy]

Does anyone have a source for the entire rotary-shock unit? Thanks, David Smith.

Those Lever Shocks are rebuildable, Generally they just need the crud cleaning out and refilling with m/c fork oil - there isn't usually much more than a piston and the occasional sprung washer/valve in there. You can tune them to an extent by using different weights of fork oil.

The Shock Links are available. GM, Ford and other brands ran them til the mid 50's.

They generally get called pieces of sh*t because when we get them, they have not been serviced if 30 or more years,

[Vladislav]

Some pics, sorry the parts weren't cleaned up.

[41chevy]

Some pics, sorry the parts weren't cleaned up.

Vlad with the "finger Washer" in the first photo, makes me think that yours are not hydraulic but friction shocks. The finger washer adjusts the drag on the discs. Paul

[Black Bull]

Thanks guys.

We've got a 51 LTL and a 43 Mack as well.

The Shock links on those are near vertical.

[Vladislav]

Vlad with the "finger Washer" in the first photo, makes me think that yours are not hydraulic but friction shocks. The finger washer adjusts the drag on the discs. Paul

Paul, that's quite interesting.

I have never put my hands on them yet, so they might be of a friction type indeed.

The links look similar to hydraulic ones, hope my images can help to figure out the general design.

[Black Bull]

Ok, Got it all set up but the shocks are full of crud.

Any idea of the correct way to dissasemble them ?

[41chevy]

Most of the MACK Lever Shocks are Delco-Lovejoy units. Some single action dampeners and some dual action shocks.

Inside is a piston (2 if they are double action), spring and cam off the lever arm. A wiper seal on the housing behind the arm. They are designed to leak some. The piston has a oil hole on it. The shock oil was supposed to be checked and topped off every 3500 miles.

I've never yet had a reason to disassembled one. Reason being the unless they were seized they can be flushed out.

I run SafeT Klean through them and work the lever to push all the dried oil out of the unit. Take a while with letting them soak in the Safety Klean between working them.

Refill with Motorcycle/ATV fork oil (medium weight oil), (Chevs of the 40's also has Shock Oil in the catalog for $9 a quart). Going up or down on the oil weight changes the dampening rate. DO NOT use Power Steering or Hydraulic Jack Oil. They do not have the needed viscosity for the shocks. This is what works for me, your unit your choice.