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Macktruckman

Eaton behind maxidyne

Question

I have a 1978 R685ST with a 285 maxidyne and the 2 stick 6 speed with 4.17 rears and tall 24.5’s. Truck is getting a new cab this week and paint job. Old cab is rusted out badly. I have an Eaton RTO14909MLL from a wrecked mixer truck with E7, I think has mounts that will work. Now would be the time to swap transmissions if I want. I was thinking it would help lower my rpm at highway speed and give me a little more top end and maybe help me out on hills. I live in an area with lots of hills. Pull a lowboy to move my equipment and pull an end dump. I like the 2 stick but the gap from 4 to 5 is pretty big with all the hills and I can only get about 60 mph or so on flat ground to the floor tached out. Transmissions look to be within 1”-2” of each other in length. U joints different. Would it be worthwhile to swap? Since the cab is off anyway 

thank you 

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Just now, Macktruckman said:

Yes Rob you’re certainly right. This was a Haldex and I thought it would be ok but not so apparently 

Haldex, (my opinion) is just about down there with china.

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It’s apparently no good. Lesson learned and it’s frustrating when the whole point of changing it was to avoid changing it after it was all together. Lol I’m fortunate enough to have a/c and I don’t really use the wing glass to hang a finger on. My old steering wheel had cracks in just the right places so as to pinch the piss out of the underside my fingers. Lol

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4 hours ago, Macktruckman said:

It’s apparently no good. Lesson learned and it’s frustrating when the whole point of changing it was to avoid changing it after it was all together. Lol I’m fortunate enough to have a/c and I don’t really use the wing glass to hang a finger on. My old steering wheel had cracks in just the right places so as to pinch the piss out of the underside my fingers. Lol

As our favorite former president used to say; "I feel your pain". Like bashing my head I've learned that type lesson a couple times too. Haldex is a conglomerate that swallowed up a bunch of good companies to reap profits by cheapening the products but riding on the names of the former good companies. Kinda like Volvo has done to the Mack Truck brand and it does take time but catches up eventually.

Never had problems with Haldex remanufacturing myself; only their new products which from what I've seen are manufactured just good enough to serve the purpose, or get it out of warranty. Not plugging for Bendix at all but I've had a lot less failures with their new parts than the other brand.

Where you'll catch a finger is in the track when the driver's window is down maneuvering in close confinements when the pain really has a chance to irritate you.

Your truck looks good. Wish I had half the talent to do that type work.

 

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I can see where you would catch a finger there with those massive steering wheels. Lol. Thank you very much for the compliment but it’s definitely no professional job. I have a really good mechanic and he was a lot of help. He’s also turned out to be a really good friend. I did a lot of it myself but I also had a lot of help from him. He actually sprayed the paint. It’s definitely not a show truck. That said, it’s definitely a different truck and definitely for the better. I appreciate his help very much. I paid him but I feel like I got far more than my money’s worth for his part. I also appreciate the help and advice from all of you guys on this forum. I’m happy with the truck. Like all of you guys and your trucks, it’s not done. It’s nice enough now that I want to do other things to it.  It probably will never be finished. Lol. But I don’t have a hotrod or anything else for a hobby really so this is my hobby that also helps me do my job. 

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Where would a guy start looking for a set of Jacobs brakes for an EM6?

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41 minutes ago, Macktruckman said:

Where would a guy start looking for a set of Jacobs brakes for an EM6?

Might try partseek.com as a start. I've never had an engine with them and the set that is on the Caterpillar engine I drive for the sod company seems to be just a noisemaker. I leave it turned off as it "drones" in the cab.

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Jake Brake 675/675A are for the 2 valve Mack engine.

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Thank you sir I just came across that with a google search myself. That’s exactly what engine I have too. 

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I`m sure i`ll get pounced on for saying this but if i were you i would save the 12-1500.00 dollars for something more useful

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I’m here for the info and experience of folks that know. None of our Mack’s ever had jakes so I don’t know. They not work good?

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We have a 475 3406E and the jakes on it make a difference on grades. But if they aren’t effective on the old Mack engines I’d be interested to hear

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Posted (edited)

we have a tandem mack rollback and a 2000 vision .the vision has the 460 eng rollback has e6 350` both are properly tuned  neither is as effective  as a 3406b loaded heavier` and no where near  as effective as a 350 cummins. I should add. that the e6 350 has genuine jacobs  set set up  not positive what the 460 is

Edited by carlotpilot

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It would make sense. More ponies pulling would probably be more ponies braking I suppose 

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to be fair since cummins was the originator of the jacobs eng . brake  their design produces the most usable braking hp of any engine that I know of . supposedly  if you have 500 pulling hp then you have 500 braking . i am told that the 60 series detroits are almost the same . we have one of those to and it works

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I was interested in the Jacobs brand brake. Not the Mack  dynatard. My understanding is that dynatard requires a camshaft change and is also less effective. All things I’ve read as I have no first hand knowledge. But if a jake won’t help any I wouldn’t want to toss away the cash for it. 

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I'd save the money too. I've rode in a few trucks with them and the 3406 around 500hp, and the Cummins about 350hp seem to work pretty well but I really don't like the noise replacing common sense when driving. My opinion may be a bit harsh but living on a busy state highway and being awoken a few times by morons operating trucks and laying on the "Jakes in the wee hours are not inviting to me.

The 410/430hp Cat C-12 engines I drive will still accelerate downhill with the trailer empty and the Jacob's Brakes on high. Maybe there is something wrong I don't know but both trucks act the same.

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Well I won’t lie, I could spend that much on trailer tires about any time. So it’s not like I just need to blow the money. Lol

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I have some questions

What 18" steering wheel did you use and do you have a picture

What insulation do you go with and how much of the cab did you do.

Do you have any pictures of your hood mounts and rollers?

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The steering wheel is an sci brand called classic polyurethane steering wheel. I got it from Raneys and I think it was the cheapest one. 

The insulation, I bought off Amazon. After some research. The first layer is a sound deadener. Something like hushmat and dynamat. I put it on every surface I could in the cab. (It’s an adhesive back) Inside the door skins. On the floor and up the firewall as far as possible. Even the bottom side of the floor pan. Up the back cab wall to the bottom of the window. The entire cab roof. Second layer was a adhesive backed 8mm thick foam. Stuck it right over the sound deadening material. Third layer was thermal insulation foam with a foil back. Then on the floor and up the firewall I layed in the factory floor mat and a layer of mass loaded vinyl for a little extra sound resistance. Put the foil back under side of the hood and outside on the firewall as much as possible.

The hood rest set was off a doner  truck. The rollers were gone but I was able to make some peterbilt replacement rollers work on my mounts/rests. The Pete rollers were like 6 bucks each. It took a little trimming and trial and error fitting but it all worked out. 

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B, and most R series trucks used a 1"X36 spline count adapter for mounting the steering wheel to the column. When ordering a wheel they usually need to know what adapter to install so it fits your column. The CH series and newer used a metric adapter. The steering wheel on my R-795 is from a CH but the adapter is from another R model. I drilled out the fasteners and changed the hub so I would quite catching that broken finger in the effn window frame!!!

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That’s clever and funny. Lol

i did order an adapter for the 1” shaft when I ordered the wheel. I probably should have said that 

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There is a cup or whatever on the top of the column under the wheel that’s held by a single Phillips screw. I should mention that on my particular truck I had to trim or grind or machine about 1/8” off the top of that cup before the new steering wheel hub adapter would clear without rubbing a little 

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Posted (edited)

Just an FYI, I put jakes on my 237.  Waste of money?  Likely for all I do with it.  BUT...I'm pleasantly surprised on how well it actually works.  For even my little 30K lb truck, it does hold it well on hills.  I was over in PA the other weekend and they have this brutal hill over by Milroy.  It held my speed without having to touch the brakes.


I'm sure if you have 80K lbs it isn't so great.  Better then nothing I suppose.   Major parts are hard to come by and pretty costly too.  I needed one lash cap(for the early large stem valve).  NLA from Mack, I posted on FB and a guy send me one for free.  Ever so grateful for FB at times like that.  Basic rebuild kits aren't bad, but if you need big pieces,  Ouch.  It was a simple bolt on.


The whole problem with Mack is the small cubic inch and lower compression then a Cat/Cummins.  That takes away from the effectiveness of a Jake.  Mine shows 5# of boost on the gauge while working.  The lil 237 only makes 15+ lbs under load.

Edited by Freightrain

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