Ref. Bob Brentwood Shock Thread

[Ed in Maine]

I was pleased to read all the threads in this post. My question deals with the fluid that you are using. Bob mentioned that he is using 85-120 gear oil which is (I think) heavier than the hydraulic fluid that I got from Snyders. My shocks are leaking out the threads and locking ring. What fluid can I use that would reduce the leakage and still provide good service on the road? Ed

[Oldbluoval]

I built shocks years ago.
The fluid won’t make a lot of difference on leaking. Of course if grease-like it might not leak but no hydraulic action
What I did was :
1. Make sure the neoprene ring seal was heavy enough diameter to get good compression between the cover and the locking ring
2. Be sure all parts are oil free when assembling the housing, cover and lock ring
3. Use non hardening Permatex on the threads of the cover. Use generously
4. Be sure the all exterior parts are tight. A proper spanner wrench will be necessary
5. Of course fill the reservoir cover after sealing!!

With the above, I had 95-98% success of non leaking. I usually let them sit and get warm (sun will do). The warmth seemed to be a motivator if they were going to leak.
If they leaked, start over with the process with neoprene, cover and lock ring!

The next thing to leak was the needle valve. I used neoprene rings as well as Teflon string

[Brentwood Bob]

Will try sourcing the stem seals. I bought a lifetime supply of the stem packing already. Winding that correctly seems to work, but trial and error on the occasional stem.
I have noticed the delayed leakers. Warm weather is coming back so a sun bath will be used. Also very clean and chased threads.i use permatex on the locking ring also. And lips of both the cover and the locking ring are free of burrs.

[jack wingard]

Originally Posted by Brentwood Bob

Will try sourcing the stem seals. I bought a lifetime supply of the stem packing already. Winding that correctly seems to work, but trial and error on the occasional stem.
I have noticed the delayed leakers. Warm weather is coming back so a sun bath will be used. Also very clean and chased threads.i use permatex on the locking ring also. And lips of both the cover and the locking ring are free of burrs.

I read somewhere at one time of a builder using the proper type of teflon tape on the threads for the caps as well as using the o-ring for the locking ring.

[BRENT in 10-uh-C]

Originally Posted by jack wingard

I read somewhere at one time of a builder using the proper type of teflon tape on the threads for the caps as well as using the o-ring for the locking ring.

As for the caps, it has been my experience the fit to the threads is already tight enough where those caps can be very frustrating to get threaded onto the body. I doubt there is clearance for a wrap of tape, ...especially when you must overlap the two ends of the tape to keep it stationary. My hat is off to that rebuilder if he uses Teflon tape in that location, ...unless maybe the cap has been swelled during the disassembly process and this was his way of compensating.


Something to think about regarding this stem. As the Rotor (Wingshaft) twists against the Stator it compresses the oil, thus creating pressure. While I would need to research this some, I would think the higher the viscosity of that oil, the higher the pressure. The higher that pressure is should mean the oil is going to find any place it can with the least resistance to relieve that sudden burst of pressure. Guess the two obvious places that is.

[Kurt in NJ]

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when cooking a shock and tossing it in water to cool the cap will shrink first because it is thin metal, perhaps this is making the thread fit looser

[Oldbluoval]

Teflon tape on that diameter and fine threads would be/is a bear. Tried in once and frustrating.
The non-hardening permatex or equivalent is about it….as I know it.
As to viscosity…yes, the thicker does stiffen worn shock action. But there are limitations as to performance.
I’ve been told that most fine point cars have dry(but lightly greased internally) shocks to avoid visible leakage. Dunno

[alexiskai]

My limited understanding is that Teflon tape is a lubricant, not a sealant, and it's designed for two uses:

• Pipe threads, i.e., interference-fit threads, to allow the two threaded pieces to be tightened farther
• Dissimilar metals, to prevent the metals from actually touching each other and galling, which would prevent the joint from being loosened

In both cases the tape itself provides no sealing action, it just boosts the sealing action of the threads. If your threads won't seal on their own, the tape won't help.

[LeonardS]

Originally Posted by alexiskai

My limited understanding is that Teflon tape is a lubricant, not a sealant, and it's designed for two uses:

• Pipe threads, i.e., interference-fit threads, to allow the two threaded pieces to be tightened farther
• Dissimilar metals, to prevent the metals from actually touching each other and galling, which would prevent the joint from being loosened

In both cases the tape itself provides no sealing action, it just boosts the sealing action of the threads. If your threads won't seal on their own, the tape won't help.

According to Google.

Why is Teflon tape used?
Teflon® Tape is a common, inexpensive, and effective thin white tape used to seal pipe threads being joined together for plumbing jobs. It is used to seal water, air, and gas from leaking through threaded connections that don't have a built-in rubber seal.

[alexiskai]

Originally Posted by LeonardS

According to Google.

Why is Teflon tape used?
Teflon® Tape is a common, inexpensive, and effective thin white tape used to seal pipe threads being joined together for plumbing jobs. It is used to seal water, air, and gas from leaking through threaded connections that don't have a built-in rubber seal.

I can cite random authorities too:

Thread seal tape is wrapped around the threads, lubricating the connection and allowing the two pieces to be screwed deeper together.

Thread seal tape lubricates allowing for a deeper seating of the threads, and it helps prevent the threads from seizing when being unscrewed.

Thread seal tape is appropriate for use on tapered threads, where the sealing force is a wedge action. Parallel threads may not seal effectively with or without tape, as they are intended to be sealed by a gasket.

-- Wikipedia

I understand that it's common to refer to PTFE tape as a sealant, but it's important to understand that it actually assists with sealing by thread interference. If you need an actual sealant because your threads will not seal on their own, you should use a liquid sealant.

[Ron Blissit]

I recently reconditioned all 4 of my shocks . Due to some clearance issues I used synthetic 80/90 gear I used the Permatex non hardening to seal any potential leaks.So far I am pleased with the dampaning action. and NO leaks.I bolted the shocks to a very large I beam and used a. 48 inch pipe wrench to facilitate opening the shocks. The wrench left a few marks the were easily removed with file and sanding

[LeonardS]

Originally Posted by alexiskai

I can cite random authorities too:



-- Wikipedia

I understand that it's common to refer to PTFE tape as a sealant, but it's important to understand that it actually assists with sealing by thread interference. If you need an actual sealant because your threads will not seal on their own, you should use a liquid sealant.

You win. Have a great day.

[ronn]

so instead of the tape- why not the liquid compound with minute pieces of teflon
in the mix? Ive always found it preferable when doing plumbing, to the tape.
always had a better easier seal........

[Oldbluoval]

Actually I consider the Teflon for water, gas, steam.
My opinion is not for grease and oil.
But that’s my assessment and from any Mfg data sheet

[vern hodgson]

I used pipe thread compound, seems to have worked.

[rogerkb1936]

i think i bought shocks from you several years ago. if so they seem to be working well. but i am writing to see what you do with carbs (not the kind you eat) i have one i would like to talk about if i i could have your fone #, thanx, roger kb

[Brentwood Bob]

Yes, glad to talk with you.,
PM sent.
Have cores, and should be able to match your build date with the correct 29-30.
Challenge now is Rebushing a worn throttle shaft hole.

[BRENT in 10-uh-C]

Originally Posted by Brentwood Bob

Yes, glad to talk with you.,
PM sent.
Have cores, and should be able to match your build date with the correct 29-30.
Challenge now is Rebushing a worn throttle shaft hole.

I have not rebuilt carburetors in awhile but is the Poulan chainsaw bushings still available?

Not sure if this is how you are doing it, but I have a 90° angle plate that I bolt to my Mill table, and the angle plate is set-up so the carburetor top bolted to the plate where the carburetor to intake flange was. I just drilled and reamed for a bushing. Is that what you are doing??

[Brentwood Bob]

Brent, Way more manual than that. Been able for most to silver solder worn shafts, or go oversize. I don't know how to operate a metal lathe, or a mill. In the next life I will learn.

[Benson]

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