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Discussion Starter · #1 · (Edited)
My new "Speedway" replacement control arms (assemblies include poly bushings) were quiet for a few miles & then started squeaking bad. I had adjusted the UCA shaft nuts with suspension loaded at ride height. So, removed one of the UCAs to investigate lube needs & found rotating the arm around the shaft felt rough/notchy & 'dry'. Removed one of the bushings & determined that there was no lubrication anywhere within the cross-shaft assembly.

Viewing several tutorials on the internet, I'm seeing where at least some poly (red/orange spool) rotates around its own sleeve but mine appears fixed as if the poly along with its sleeve operate as an assembly. So my question is since I see where poly lubrication should be PTFE, silicone grease or even anti-seize ---- where do you apply it? Does it go between the shaft and the inside diameter of the poly sleeve or between the outside diameter of the sleeve & the inside of the poly spool? I can't see how I could remove the sleeve from the poly spool w/o damaging one or the other.

Never dealt with poly bushings before or even gave bushings much thought period. Pls Help, Thanks!!
 

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From what I can gather off the net , poly bushing don't " twist" like rubber bushings. They actually rotate on the sleeve & housing . It would seem that they require grease during assembly . some even have zerks & channels cut in them so they can be greased in place . One of the major complaints is SQUEAKING ! Have you spoken to speedway tech about your concerns ? Seems that would be a good place to start .
 

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When installing/using poly bushings it is imperative you use liberal amounts of the appropriate silicone grease designed for the poly bushing (correct grease does not attract dust/dirt).

Poly bushing operate/rotate like bearings, they do not stretch or move like rubber, they need liberally applications of silicone grease to all contact areas (inner and outer) to assure smooth noise free operation over their lifespan. This should be stressed and identified in the installation instructions. Buy additional poly grease, there is seldom enough supplied (if any) with the bushings. Silicone poly grease is relatively cheap, you can not use too much, slather it all over the bushings and mating components, clean up excess after assembling (if needed).

My poly bushing have been in for several years with no noise or problems. Poly bushing do tend to ride a little firmer and give more road feedback to the steering (road surface deformities are felt more), which may not be desirable to all situations/individuals.
 

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Poly bushing are not a press fit in the same manner as rubber bushings. Their race (outer sleeve) is press fitted, the poly bushing itself can be removed and greased, as well as the inner race can be removed and greased.
 

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Discussion Starter · #5 ·
From what I can gather off the net , poly bushing don't " twist" like rubber bushings. They actually rotate on the sleeve & housing . It would seem that they require grease during assembly . some even have zerks & channels cut in them so they can be greased in place . One of the major complaints is SQUEAKING ! Have you spoken to speedway tech about your concerns ? Seems that would be a good place to start .
Yeah, I had several discussions with Speedway Techs & about the only advice I got was to just spray them on their edges with silicone or penetrating oil the night before intallation. There are no zerks. I removed one of the bushings & found that neither them nor the shaft have grease channels. The bushings are assembled just like the rubber OEMs with the inner sleeve being part of the assembly. The only difference I can see in the construction of the cross-shaft from OEM (besides the color of the poly) is that the shaft does not have the serrations that would lock it with regard to the bushings (which do have serrations).
 

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Discussion Starter · #6 · (Edited)
Poly bushing are not a press fit in the same manner as rubber bushings. Their race (outer sleeve) is press fitted, the poly bushing itself can be removed and greased, as well as the inner race can be removed and greased.
Yeah, that is what I have seen on the internet. The poly bushings themselves cannot be removed from the outer sleeve. The inner races are press fitted into the poly & won't budge. The assembly is built identical to the rubber OEM, only visible difference is the red color & texture of the poly.
 

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Discussion Starter · #8 ·
I'm on the verge of labeling these upper control arms as poor quality/inadequate design but am seeking concurrence and/or correction from you folks here. Had several conversations with Speedway Techs who say the UCAs are correct the way I'm describing them but I have doubts. Since the cross-shaft does not have the normal serrations (saw-teeth) on either end where the bushings mate to the shaft, there is no connection between the frame of the car and the polyurethane material pressed into the bushing. In a typical poly bushing, the poly rotates around the inner sleeve/race & also within the outer sleeve which in turn presses into either side of the UCA. The poly gets lubricated on its ID & OD & this joint/assembly dampens the motion of the chassis as the arm rotates (the same way a rubber bushing dampens as the arm rotates & twists the rubber). The shaft & bushings remain stationary while the arm cycles.

With the UCA I have the bushings consist of the outer sleeve, poly & inner sleeve/race all pressed together as an assembly identical to an OEM type rubber bushing with the exception of the poly. The result is the poly bushing is simply rotating around the shaft in a metal to metal contact (inside of inner sleeve to the shaft) & chafing,creaking and scrubbing along the way. The bushings cycle with the arm while the shaft remains stationary. The poly may as well be metal. The OEM rubber design IMHO is far superior & this all seems an attempt to showcase the use of the poly material which does not seem to be functional at all. The only dampening of the chassis motion is the metal friction between the inner sleeves & shaft. The only way to add any usable lubrication is to disassemble the cross-shaft by removing a bushing & applying grease or silicone between the shaft & inner sleeves. The procedure of waiting until the chassis is loaded & at ride height before torquing the shaft nuts is of no consequence since the shaft is not connected to the bushings. Also, just for the record, the bushings do have the typical serrations (saw teeth) that would normally mesh with the shaft.
I hope I'm not over-thinking this & situation is not as bad as it seems. Please chime in!!
 

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You don't want any rotational damping from the bushing...that isn't its job and would be counterproductive to performance handling. The shock is meant to be the sole damper in the system, for a high performance handling suspension you want the upper and lower a-arms to move as freely as possible, as to not influence spring rate or suspension reaction to bounce and rebound.

The poly bushngs I'm familair with get lubed on all surfaces so they don't grab at anything, and the inner sleeves have no end serrations either.

Ideally, with the upper and lower A-arms and spindle all assembled with out the spring or any brakes it should be capable of easily being moved by hand to maximum compressed, then released and gravity immediately dropping it to the bottom of it's total travel....no friction at all. Every poly bushing I've ever used got completely greased with silicone grease before the inner sleeve was installed or the bushing pushed into the outer sleeve. Large washer on the end of some style also got gerously lubed on the side that contacts the bushing lip.

That's the main reason the multi-piece high end Del-A-Lum( delrin and aluminum) style bushings were developed, to go one step even better than polyurethane. Unrestricted movement along with minimal deflection.

Sounds like maybe you've just got some poorly designed aftermarket parts? Wouldn't be the first time in the street rod market, or from Speedway(and many others).
 

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Discussion Starter · #11 · (Edited)
You don't want any rotational damping from the bushing...that isn't its job and would be counterproductive to performance handling. The shock is meant to be the sole damper in the system, for a high performance handling suspension you want the upper and lower a-arms to move as freely as possible, as to not influence spring rate or suspension reaction to bounce and rebound.

The poly bushngs I'm familair with get lubed on all surfaces so they don't grab at anything, and the inner sleeves have no end serrations either.

Ideally, with the upper and lower A-arms and spindle all assembled with out the spring or any brakes it should be capable of easily being moved by hand to maximum compressed, then released and gravity immediately dropping it to the bottom of it's total travel....no friction at all. Every poly bushing I've ever used got completely greased with silicone grease before the inner sleeve was installed or the bushing pushed into the outer sleeve. Large washer on the end of some style also got gerously lubed on the side that contacts the bushing lip.

That's the main reason the multi-piece high end Del-A-Lum( delrin and aluminum) style bushings were developed, to go one step even better than polyurethane. Unrestricted movement along with minimal deflection.

Sounds like maybe you've just got some poorly designed aftermarket parts? Wouldn't be the first time in the street rod market, or from Speedway(and many others).
Many thanks for your concise response, it opened my eyes to a lot. My initial desire was to get the suspension as quiet & as smooth as possible with no consideration to high performance operation (since car is strictly a cruiser). That is why I wanted the OEM style dampening of the UCA. I understood your comment wrt friction free motion as well as serrations not being necessary w/o the rubber bushings & that caused me to take another look at what I got from Speedway. I completely disassembled one of the cross-shaft assys using a hydraulic press to force the center sleeve & in-turn the poly from the outer sleeve. This had seemed impossible until I used the press & found the smoking gun (I think). I found that the inner race/sleeve had a heavy coat of black paint on the outside, some of which remained adherred to the inside of the poly piece. Additionally two out of the four outer sleeves had an undressed weld on the inside making for a more restrictive fit.

Don't know if I should have but I sanded the paint off the inner race/sleeve & used a Dremel to smooth the welds on the inside of the outer sleeves. I put it all together with silicone grease slathered over everything & lo & behold the assembly slides/rotates smoothly with little friction. So my original thought was that the design was snafu but after your comment about the desired free movement of the arms and re-looking at what I had, I now think the biggest problem was the assembly of the pieces (should the paint have been applied?) plus the fact that there was no evidence of lubrication at all anywhere except between the inner race & the shaft. So Plug n' Play they definitely weren't. Maybe I created clearance that shouldn't be there but it seems to be working fine. The smooth movement is fine without the dampening I thought I had to have. If you think I messed up, pls let me know. THANKS Again!
 

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Sounds to me like you found the fix.
In retrospect, I would have polished the paint off the outside of the inner sleeve, and made the outer sleeves ID as smooth as possible too, then lubed everything for reassembly. Basically, "blueprinting" the assembly.

Poly is used in place of rubber because the poly is much stiffer....it doesn't deflect under load as much as rubber and cause handling or alignment issues, plus it is much more durable than rubber. Trade-off is that it can be a harsher ride if not countered with correct spring rates and shock absorber design/settings. A step further along the handling path is Del-A Lum, which are aluminum bushing with a shin delrin sleve on the Od and ID to even further combat deformation. Then comes the ultmate, a rotary bearing or greaseable solid ball bushing type of deal.

OEMs used rubber because it is cheap, combats vibration and noise transfer from susension to cabin, and it's cheap. Yes, I said cheap twice....Lol
 
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