VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 knee action leaking top arm

how hard is it to remove and rebuild knee action ?? has anyone tried 85-140 gear oil in these units ? sc

Without access to a machine shop, and experience, knee action shocks are not rebuildable. Filling a shock with a heavier grade oil only slows down the ability of the shock to react to road conditions and will not stop a leak under pressure.

I strongly recommend Apple Hydraulics as a reliable source for rebuilt shocks. Info about them is on their web site Apple Hydraulics.

It usually does not make sense to replace only one shock. The other side is probably close to leaking. What does make sense is to complete the work on one side before taking the shock off on the other. Your OTHER shock will serve as an excellent reference. Make a video of all the steps you use for another reference on reassembly.

Good luck, Mike

P.S. There is a link to an outstanding post on how our SEARCH process works Searching for old posts.

140 Gear oil will stop the leak and the movement of the arm.
The ride will be a stiff as a board.

I removed all of my hydraulic shocks after following the procedures in the service manual.
As Mike Buller stated above, I sent all 4 to Apple Hydraulics. Some of the venders we use offer to rebuild shocks for you. I think they send them to Apple Hydraulics. Skip them, and go straight to the source. I'm very happy with their work.

Good luck!

Curt

You can remove the nut, which is locked in place by a lock stud, and you should be able to view the needle bearings. If any are missing, then it is damaged and will need to be rebuilt.

If they appear to be okay, then check the inside of the nut for a packing type rope. Either add to it or replace it and reattach the nut and secure with the lock stud. Fill with jack oil. (be sure the weight of the car is on the front suspension) Check it a few days and tighten the nut until it stops leaking.

This only works if the needle bearings are okay. Mine had been rebuilt by a PO and they have a bushing inplace of the needle bearings.

There are not supposed to needle bearings in a 38 model..my idea is to clean outside of arms and wrap rubber tightly around pivot area and fill with 85-140 gear oil ..I'm to old to get a stroke working this design nightmare..can't even replace with straight axle,only options are to cut front off and weld a master front end on ..lots of fun..sc PS an old trick on leaking auto trans is to add brake fluid to swell robber seals ..??

All enclosed knee-action units had needle bearings. If they were rebuilt at one time they will have bushings.
It is the king pins that had needle bearings from 1934-1936, 1937 and 1938 having bushings. The replacement king pin sets for 1934-1936 have bushings.
There are no rubber seals to swell, the seals were cork. Also you can tighten the packing nuts. If any of the cork remains this will squish it.

Have you ever had an automatic transmission apart after that "overhaul" trick ?? I have. Anything that that will fix leaking seals from a can only makes things worse and a real mess.

Gear lube of any weight will not allow the shocks valves, located in the knee action, from functioning properly and will produce a horribly stiff ride.

As for the nut I talk about, it will move far enough in the off position that you can repack it. Granted its not user friendly, but with patience and with slow deliberate approach it can be fixed.

Believe me when I say we are all cheering for you.

There was an article in the G&D several years back telling how to repack the seal around the arm. It was written by an automotive journalist with my help. It is a few pages long. I can send you the article if you want to see what you can do.

Great info on a subject without much info..cork it is then,I will try to tighten 3" nut..also chevgene I would like to see that article about repacking to bad you couldn't post it for others to see.but do you want my email or post office address ? I like the car and hate to move it down to a hot rodder but may have to..Spencer

I have your email adress. Will send later.

I have never messed with the 38 type knee action but here is my tqke on fixing leaking or worn out ones. Bite the bullet. Take the sucker off and send it to Apple Hydrolics and get it fixed right. Anything else is like putting a "Bandaid" on a bad knee. You may think it will work better but it won't.

Whatever the cost it will be worth it. You just can't fix the stinkin things yourself. As Andy used to tell Aunt Bee when an home applience went bottoms up, "Call the man." Good advice. Andy was the sheriff not a repairmen.

I think the 38 type front shock was a great item when it was working correctly. I drove a 37 for a short time that was equipped with them and it road real good.

Good luck,
Charlie

It seems spending $500 on new shocks is much cheaper than any hot rod alternative.

Unfortunately, a lot of our vintage cars are turning up as hot rods. It would be nice to recycle the parts removed to vintage car enthusiasts. Deciding whether to repair or update a major system of a car is always a slippery slop. Not liking the suspension, steering , engine, transmission, rear end, brakes,etc. leads one down the path of hot rodding. I worry what will happen to my 41 when I die or must get rid of it?

Thanks, Mike

P.S. There is not much money in reselling parts. There is the satisfaction of knowing you have helped others in maintaining or restoring their cars, and know the parts did not end up sold as scrap metal.

Mike they are not just shocks they are complete front suspension with shocks built in..they $650 each to rebuild with core sent back plus shipping to New York from Calif , they are very heavy and big and difficult to remove,the rebuild fee is only if my old knees are in good shape if they find excessive ware then the price goes up..its easy to get $2000 to $3000 invested in these stinkin things, that's half of what I paid for car..sc

FWIW & my two cents, when I go to most any car event other than a VCCA event every '38 I see, other than mine, is a hot rod. Because of that the value of my stock '38 has gone through the roof according to my insurance company. In an effort to not spend $10-20K keeping their cars stock, the owners spend $40-50K turning them into hotrods then wonder why they can only get $20-30K when it's time to sell them. Admittedly it's rare for anyone to get the money back out of their car that they put into them, whether hotrod or stock, but it's sad when I see another original car turned into a hotrod, a passage there's no return from. Another piece of history lost. At the end of the day the car belongs to the owner so if they decide to turn it into a hotrod or a backyard planter it's their decision and all we can to is watch.

What I would like to do maybe is to find 37 to 39 stock running gear straight axle Master and put this body on it..sounds like a lot of work and headache either way I go, should have been more educated on these knee action jobs before I bot it,hard lesson learned I guess..sc

Gene has posted in the past that in the day it was not uncommon for folks to swap the knee action front ends out for a straight axle off of a Master. That avenue may be open for you. I used to see Master frames with the suspension attached on ebay all the time cheap. I don't do ebay much any more so I don't know if that's still the case.

A 1938 body will not fit on a 1937 frame.
Fill the shocks with some 10w-30 oil and see what happpens. The knees will leak whe the car is jacked up and the wheels hanging down.
The 10-30 will firm up the shock action, especially in cold weater but will make OK for a test. Each unit holds about 2 Qts.

Tiny , I was told a straight axle will not fit a Master deluxe frame , If this is possible I may go that route..Spencer

Looks like the front cross member is different. It could be as simple as removing the MD crossmember and replacing it with the M. The rest of the chassis looks to be the same.

Possibly a better chance would be installing a 1939-1948 front cross member with the open spring knee-action attached.

My advice still stands. Bite the bullet and get the suckers rebuilt. All that swapping may not going to lead to a satisfactory outcome. Having them rebuilt will. The car will steer well and ride like a RR. Well, sort of.

Charlie

If your car is drivable with no wandering and there is no unusual wear patterns on the tyres then there is a fair chance the knees are okay and only need new seals. I have done the knees on both my 1934 master and my 1935 master by myself for a total cost of less than $200. All four knees had bushes installed probably in the 1950s and only two required new bushes. I installed modern seals NAK brand size 42x55x7.(had to take a very small amount off the outside diameter). The ones in the 35 have been in for 19 years and still don't leak. They really are not that hard to work on.