Gunsmoke

1930's Delco-lovejoy Duodraulic shock rebuild

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Planning on rebuilding/refurbishing the 4 Delco-Lovejoy "duodraulic" shocks off my 1931 Chrysler CD8 project, one each for front and rear shown here. I don't have any literature on them, note they have a large "allen type"  end cap. 2 large access screws (to get to valves?) and a smaller screw (for filling?).Also have a gasketed plate secured to side with 4 screws, giving access to end of lever shaft. Anyone have a "one-pager" on rebuilding/servicing  these? or any other advice? Are rebuild kits available? I see Steele's sells the rubber grommets for connecting rods. These shocks were sandblasted, but have been dormant for 50-60 years or more, but arms move up/down. May need to apply some heat to free up screws/endcap. Thanks.

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Benefits of AACA Membership.

I've rebuilt a few of the early 30's Delco Lovejoys.  It can be done, but not easily. You'll need to find, or make some special tools.

 

Make sure you keep track of where each of the spring-loaded restricting valves - that are in under the screw-slotted covers - comes out of, or they won't work as they should.  Up/down and front/rear often have different spring tension valves.

 

To properly clean them the end caps should be removed. That takes making a tight-fitting clamp out of wood and wood clamp so as not to bugger up the cap's splined outer edge like the jaws of a pipe wrench will. A strap wrench doesn't grab well enough.    And you may have to heat the cap to expand is and get it to relese after alife time of being tightened against an aluminum seal washer.

 

The arm needs to removed from its shaft so that the piston can be removed to properly clean it and the bore. That takes a torch and a gear puller and a fair amount of cuss words and bandaid or duct tape to get the bleeding fingers under control.

 

I had to make the hex tool and cap clamp to get them apart. And even then, they can be very tough. There's an aluminum seal in behind the edge of those covers. Don't use any other type of gasket material or else it won't hold against the very high hydraulic pressure of the piston action in use on a bumpy road.

 

Regular hydraulic  jack oil is used in them. Fill only to the bottom of the fill-plug hole when the shock is held level. Work the arm up and down fully to bleed all the air out of the end chambers. Then recheck the oil level.

 

Or, do as I do now, rather than fight them apart. I now send them to Apple Hydraulics and let them rebuild them. They do excellent work. ... and I do less cursing,.... and less bandaging of fingers.

 

Paul

Edited by PFitz (see edit history)

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3 hours ago, Gunsmoke said:

Planning on rebuilding/refurbishing the 4 Delco-Lovejoy "duodraulic" shocks off my 1931 Chrysler CD8 

There was a thread in the Dodge and Dodge Brothers Forum about this. @robert b found the patent and I posted a more readable version (fixed the OCR mess). Let's see if I can find it.....  here.

You might be able to get more info. with a p.m. to Kevin.

Edited by Spinneyhill (see edit history)

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Thanks Spinneyhill & PFitz for the leads, I've copied the patent pdf info, good explanation of how they work, and also had a look at Taylormade's thread. His are not at all similar, more like the single acting shocks on my '31 Chevrolet. Between the various threads I should be able to figure out how to disassemble them carefully (not mixing up the small parts for example), and see general condition inside. Not sure if there are seals/gaskets etc other than under the end cap and access plate. I may take a couple by the local hydraulics shop and see if they rebuild them and price. BTW I have a second somewhat similar set that have knurled end caps without the "allen' head hex. 

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Use motorcycle fork oil. It com s in a large selection of weights, I start with 10 and then adjust up or down. It comes in grades:

 

0

5

10

15

20

30

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Looked on Apple's on-line site, their posted price to rebuild is about US$350 per shock plus 2 way shipping, so perhaps close to $2000 for set of 4, yikes. Thinking it might be worth a few cuts, bruises and bashed knuckles to try it myself! May just clean them out and re-fill and see if any leaks. Cheers

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I should have made it clear the wooden clamp is for the female threaded knurled end cap type off on the left in your picture. The hex tool is for the male type in the center of your pictures.

 

There are also aluminum washers under each valve cap, and a gasket for the side cover. And you'll need to replace the arm shaft seal. Last set I did, a modern replacement for the seals was still available from a bearing supply house.

 

Considering how much work they are to disassemble, clean, and reassemble properly, with the right type new gaskets and seal, $350.00 each is not bad.

 

Paul

Edited by PFitz (see edit history)

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Pfitz, in your original post you said arm needs to be "removed from it's shaft". I assume you also mean shaft has to be removed from housing (can that not be done without separating arm from shaft?)? If yes, I assume shaft is a press fit into housing, and can be pressed out after side plate is removed, using a vice or hydraulic press, etc. I'm still thinking I may drain these (by removing valve assemblies), slosh around some suitable solvent (like lacquer thinner), clean with compressed air, and clean valves, let them dry out, and try just refilling with hydraulic jack oil and see what happens. Would be nice if I don't have to fully dis-asssemble. Car they came off had 31,000 miles, so these were not long mileage units.   

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To get the double ended piston out  so you can clean the bore, the piston, and the ball check valves and seats that are imbed in each end of the piston, plus get the arm shaft seal out and a new one pressed in, you need to get the arm off the shaft's tapered spline and then take the shaft out of the piston through the cover plate hole. Then the piston can be slid out the hex socket cap end.

 

The arms are a press fit onto the tapered spline of the shaft. they take  tremendous amount of force to come off using  blocks to support the body and a strong hydraulic press. It's so much force that  you'll think something is going to break. I use a 12 ton press and it can just barely  handle pressing the tapered spline shaft out of the arm.

 

Paul 

Edited by PFitz (see edit history)

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They are not difficult to rebuild. Just time and tools. 

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Thanks for further dis-assembly info PFitz and for the DIY encouragement edinmass. Will keep you posted once I have one opened up. Have a colleague with a nice press, so he should be able to separate arm and shaft if necessary.

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Boy, totally different than the Lovejoys on my 32 Dodge Brothers.  I have a step by step in my thread, but it won’t help with your shocks.

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After using several different well known companies to rebuild shocks over the years, and having poor to terrible results, including poor workmanship, poor paint, and reuse of rusty and pitted parts, we began to do them ourselves. The trick is to have spare shocks, having extra parts, and being able to experiment with what will and will not work is much easier with spare units on the shelf. I have had rebuilders ruin shocks trying to get them apart, when we were able to do it easily. Just keep the original valving  and springs  organized so you can be sure you have the right parts in the right shock. 

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So today I tackled them. First the good news, I removed the fill plug for both front shocks and drained out the old oil which was in near perfect condition and almost full. Amazing considering these shocks have been sitting on a car for about 60 years un-used. I refilled them with new hydraulic oil and they appear to work perfectly, no evidence of any leaks, and stiff on rebound, less stiff on upwards movement. So they may be just fine.

 

One rear was dry when filler plug was removed, but had full movement. When filled with oil, decent/acceptable resistance in both directions, but is leaking at shaft/arm seal, so will need some attention. The second rear was also dry, and it has only partial movement, when filled it has no resistance in either direction. We removed the valve plugs and the valves are clean and working, so suspect piston is seized in cylinder, so this one will need full dis-assembly. So about 65% good news.  Will post some pics once I have one fully dis-assembled.  If that job goes as easy as edinmass promises!! I may take them all apart eventually.

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If the arm moves and there is no resistance with it filled with oil, and the springs  close the valves against their seats, then the ball checks in the ends of the piston are not seating. They often rust and get jammed in the open position,  or get so rusted they can't seal when seated. 

 

Paul

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Today I checked out the other 2 rear shocks I have, the ones with the knurled end caps both ends. Both work very well when filled with hydraulic oil (one was still full),  good resistance in both directions, no leaks, even though sitting for many years. While they are slightly different vis-a-vis design/looks, mounting bolt size (9/16" versus 1/2"), and mounting bolt alignment (straight line versus offset), bolt spacing is same and lever arm length and end socket is same, so they will work fine. Only requiring slight enlargement of one mounting hole and drilling a new hole for the second bolt (I may weld slug in old hole). Interestingly, the offset bolt pair (with hex end cap) and with an S curved arm came directly off an early CD8 Sedan. The knurled end cap set came from Rob in Maryland and had very old tag reading "1931 Chrysler CD8 rear shocks, came off parts car with no body". May have been from a model 77 or similar model, who knows, I understand they were removed as parts decades ago. CD8's were subject to many changes over their manufacturing run from summer of 1930 to spring 1932. Since the rear shock is completely hidden up under chassis and behind rear wheels, no one is likely to ever notice difference from front shocks. I'll retain originals of both sets of 4 in case a future owner 50 years from now gets picky!! 

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The knurled double end cap models started showing up in late 1931 on one other make I know of that used them. They were just a later design than the hex socket single end cap  Lovejoys.

 

Paul

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Thanks for that PFitz, I wasn't sure which came first. Sounds like perhaps the CD Deluxe, the so-called 3rd series (which had a million changes from the earlier series), may have worn these knurled end units. The knurled front shocks have a different bolt pattern than the hex cap fronts, and I understand they were mounted to the rear of the front fender brace (instead of ahead of it) thereby making them more hidden. I must check the knurled fronts and see how they work, I could easily drill a couple of 9/16" holes and use them instead, no one will know!! 

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So knurled cap fronts work perfectly, so I am going to clean up and use the full set of knurled shocks from a later series CD8. I'll likely part with the other 4 "hex end" shocks, 2 work great (the fronts), rears need some attention, if anyone is interested, send me a PM. and thanks all for the advice/encouragement. Cheers

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