Throttle cable lubrication?
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From: South Florida
Throttle cable lubrication?
So the throttle has always been, to my mind, a fairly high-effort throttle, relative to all my other cars. It seems a bit worse now (I haven't removed it or anything...I did an intake refresh but really didn't mess with that cable much at all.
It seems like there is enough friction now that I gently push, nothing happens, then I push harder and suddenly I'm roaring off. It just seems harder to gently push the throttle only enough to quietly move from a standing start. Is there some sort of lubrication of that throttle I can do? I've searched and I see a lot about throttle cable adjustment, but this feels like something else to me..
It seems like there is enough friction now that I gently push, nothing happens, then I push harder and suddenly I'm roaring off. It just seems harder to gently push the throttle only enough to quietly move from a standing start. Is there some sort of lubrication of that throttle I can do? I've searched and I see a lot about throttle cable adjustment, but this feels like something else to me..
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From: Denver, CO
My 86.5 always felt this way, too. You can remove the throttle cable from the front of the engine, and drip some lubrication onto the cable (the same way people lubricate premade bicycle control cables). The cable could be dirty or frayed, but...
My cable was stretched and no longer giving me full throttle, so I recently replaced it. expensive, but the original did last 32 years. The new one feels the same as far as required force. The return spring on the throttle body is pretty robust. Take the throttle rod off the front of the engine and actuate the throttle by hand and you'll see how much force it takes!
I then moved the bottom of the throttle pedal close to my seat (there are adjustments!), and that made the pedal a little less vertical and I feel like I do a better job actuating the throttle in a smooth manner.
My cable was stretched and no longer giving me full throttle, so I recently replaced it. expensive, but the original did last 32 years. The new one feels the same as far as required force. The return spring on the throttle body is pretty robust. Take the throttle rod off the front of the engine and actuate the throttle by hand and you'll see how much force it takes!
I then moved the bottom of the throttle pedal close to my seat (there are adjustments!), and that made the pedal a little less vertical and I feel like I do a better job actuating the throttle in a smooth manner.
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Many of the S4 throttle quadrants I have taken apart, had bad bearings and were eating into the quadrant shafts...that caused binding. Had worn lips on the shaft and sharp lips.
My first S4 was so badly worn, it would stick and hold the throttle open some.
83-86: 92811067900, 92811068000
87+: 92811069600, 92811069700, 92811069800
Specifically, the bearings in these for the S4+ are "HK0810-RS DRAWN CUP NEEDLE BEARING", and you need 2 per lever, a total of 6. They press out and in pretty easy.
Not sure what the 83-86 want, but likely the same.
My first S4 was so badly worn, it would stick and hold the throttle open some.
83-86: 92811067900, 92811068000
87+: 92811069600, 92811069700, 92811069800
Specifically, the bearings in these for the S4+ are "HK0810-RS DRAWN CUP NEEDLE BEARING", and you need 2 per lever, a total of 6. They press out and in pretty easy.
Not sure what the 83-86 want, but likely the same.
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From: Oman
I found that oiling with sewing machine oil helps. Add a few drops of the oil over about 2 inches of the cable surface just in front of where it enters into the firewall and work the throttle. Do this a few times and see how it goes. If the cable is damaged at all then it will not solve your issue but no harm done.
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From: South Florida
Thanks for the advice, I'll try some of that and see if it helps. I'd rather not remove the intake again to get to the throttle body, of course!
Then again, I may have a small leak at the water bridge, I'm not sure :-(
Then again, I may have a small leak at the water bridge, I'm not sure :-(
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Chronic Tool Dropper
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OP: The second cable between the quadrant bellcranks and the throttle boy passes over a wheel at the rear of the manifold. Your "sticks then roars" symptom is typical to poor cable routing at the wheel. You can inspect that area with the air cleaner housing removed. Easy enough to remove that secondary cable, flush it and lubricate it with [pick your lubricant]. Dry lubes normally get my vote for this duty.
Verify the the wheel itself rotates freely. You can remove it for cleaning and lubrication. Make sure it's still round.
Look to see that there isn't a fuel line interfering.
Make sure the throttle itself opens freely. If you had that throttle and shaft apart for bearing and seal replacement, remember that the plate needs to go back in the way it came out. There's a stop screw that holds the throttle plate just slightly off the "wedged in the closed position". The adjustment on that screw can be touchy -- too far open and the car won't idle well.
With the secondary cable disconnected at the quadrant, check to make sure that the pedal works freely as it pulls on the cable to the quadrant.
For automatic cars, disconnect and test the TV (kickdown) cable that runs to the transmission.
Verify the the wheel itself rotates freely. You can remove it for cleaning and lubrication. Make sure it's still round.
Look to see that there isn't a fuel line interfering.
Make sure the throttle itself opens freely. If you had that throttle and shaft apart for bearing and seal replacement, remember that the plate needs to go back in the way it came out. There's a stop screw that holds the throttle plate just slightly off the "wedged in the closed position". The adjustment on that screw can be touchy -- too far open and the car won't idle well.
With the secondary cable disconnected at the quadrant, check to make sure that the pedal works freely as it pulls on the cable to the quadrant.
For automatic cars, disconnect and test the TV (kickdown) cable that runs to the transmission.
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Many of the S4 throttle quadrants I have taken apart, had bad bearings and were eating into the quadrant shafts...that caused binding. Had worn lips on the shaft and sharp lips.
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On your GT, the throttle "quadrant" is missing #4, the TV cable used only with the automatic transmission. The assembly bolts to the left (drivers on US cars) side of the intake manifold. The cable from the skinny pedal and the cable from the cruise control servo both "pull", and the cable to the throttle body under the rear of the intake manifold "is pulled". Inside each of those bellcrank levers is a shaft from the mounting plate, with the little roller bearings that Speedtoys mentions. The rollers ride directly in the shafts, so when they lose lubrication the hard bearing rollers will wear the shafts. The shafts see the radial loading from the effect of the return springs, so really need to have lubrication or risk the relatively soft shaft metal.
The throttle body itself has two return springs, redundant for safety. While it may be tempting to remove one of those to soften seemingly high pedal effort, all is lost when the remaining spring breaks and the throttle moves open. Take careful pictures of the spring installed positions when you disassemble the throttle body for new bearings/seals, and put it back together the same way. It's way easy to get the springs in wrong, and add tension to the system. There are numerous threads on RL with pictures of this stuff, but having your own is handier.
The throttle body itself has two return springs, redundant for safety. While it may be tempting to remove one of those to soften seemingly high pedal effort, all is lost when the remaining spring breaks and the throttle moves open. Take careful pictures of the spring installed positions when you disassemble the throttle body for new bearings/seals, and put it back together the same way. It's way easy to get the springs in wrong, and add tension to the system. There are numerous threads on RL with pictures of this stuff, but having your own is handier.
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^^^^^^^^^
thanks
I looked up the part numbers speedtoys provided, and checked reference in the PET, and they only show the bearings
as a complete assembly with the levers at $67. each. are these bearings available separately?
thanks
I looked up the part numbers speedtoys provided, and checked reference in the PET, and they only show the bearings
as a complete assembly with the levers at $67. each. are these bearings available separately?
Chronic Tool Dropper
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Look further in Jeff's reference and see the generic bearing number HK0810-RS for the S4+ cars with the described quadrant. Take that to your favorite roller-bearings-b-us outlet and get the ones you need.