Bump felt through Steering Wheel

[billvv]

Driving down the road at 60 or so, I find myself correcting left and right due to - I think - tramlining since it tends to go away on smooth roads.
But that's not the issue I'm concerned about....

When I correct back to the left, I feel bumps through the steering wheel while the wheel is held steady - meaning that there are no bumps when turning
the wheel, but bumps when the wheel is held with the wheels pointed slightly left. Something like 10 bumps with the wheel held left for 2-3 seconds.
Once in a while I think I notice a bump or two when steering to the right as well, but I can't be certain.

Prior to noticing this (although it may have been there since we acquired the coach a year ago), I'd corrected the lower steering column/steering box
angle, cleaned and re-lubed the balls in the lower steering column CV joint (in place, didn't remove the balls), replaced the front calipers with 80mm
(including grinding to fit), replaced the relay arm and drag link, and aligned toe-in to zero.

What can be causing this?
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015; Since arrival: New HVAC blower, heat flap cable, headlight switch.

 

[sgltrac]

to rule out a tire/wheel issue you could rotate the tires in front with a
couple of the rears and see if the "bump" changes or goes away.

Sully
77 eleganza 2
Seattle

On Mon, Oct 17, 2016 at 10:34 AM, Bill Van Vlack
wrote:

> Driving down the road at 60 or so, I find myself correcting left and right
> due to - I think - tramlining since it tends to go away on smooth roads.
> But that's not the issue I'm concerned about....
>
> When I correct back to the left, I feel bumps through the steering wheel
> while the wheel is held steady - meaning that there are no bumps when
> turning
> the wheel, but bumps when the wheel is held with the wheels pointed
> slightly left. Something like 10 bumps with the wheel held left for 2-3
> seconds.
> Once in a while I think I notice a bump or two when steering to the right
> as well, but I can't be certain.
>
> Prior to noticing this (although it may have been there since we acquired
> the coach a year ago), I'd corrected the lower steering column/steering box
> angle, cleaned and re-lubed the balls in the lower steering column CV
> joint (in place, didn't remove the balls), replaced the front calipers with
> 80mm
> (including grinding to fit), replaced the relay arm and drag link, and
> aligned toe-in to zero.
>
> What can be causing this?
> --
> Bill Van Vlack
> '76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath,
> Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o
> mid
> November 2015; Since arrival: New HVAC blower, heat flap cable, headlight
> switch.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Ken H.]

Bill,

Have you tried making tight turns, especially to the left, in a large
parking lot? You want almost full lock, but not quite, turns. If you feel
roughness similar to your "bumps", I'd suspect worn CV joints, especially
the left one.

As for the "tramlining", which I assume is your term for what we here
generally call "rut following", you should consider "true-tracks" on the
center wheels. If you're not familiar with them, they're cam followers
(large caged roller/ball bearings) mounted on the rear of the suspension
arms. Those run in vertical tracks attached to the frame rails so that the
suspension arms are constrained from lateral movement. Without those, the
best description I know for the center wheels is that they act like
one-handled wheelbarrows. The true tracks are the best single thing I've
done to my GMC's handling during 18 years of doing 'most everything.

HTH,

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc., etc.
www.gmcwipersetc.com

On Mon, Oct 17, 2016 at 1:34 PM, Bill Van Vlack
wrote:

> Driving down the road at 60 or so, I find myself correcting left and right
> due to - I think - tramlining since it tends to go away on smooth roads.
> But that's not the issue I'm concerned about....
>
> When I correct back to the left, I feel bumps through the steering wheel
> while the wheel is held steady - meaning that there are no bumps when
> turning
> the wheel, but bumps when the wheel is held with the wheels pointed
> slightly left. Something like 10 bumps with the wheel held left for 2-3
> seconds.
> Once in a while I think I notice a bump or two when steering to the right
> as well, but I can't be certain.
>
> Prior to noticing this (although it may have been there since we acquired
> the coach a year ago), I'd corrected the lower steering column/steering box
> angle, cleaned and re-lubed the balls in the lower steering column CV
> joint (in place, didn't remove the balls), replaced the front calipers with
> 80mm
> (including grinding to fit), replaced the relay arm and drag link, and
> aligned toe-in to zero.
>
> What can be causing this?
> --
>

 

[terry1]

Cupped tires on the front, worn out or dry and dusty CV joints, loose CV axle bolts at the final drive connection, and loose/dry wheel bearings. These
all apply if the vehicle is moving when steering. If it is not moving, check the relay arm for freedom of swing and the rest of the suspension joints
per the Rob Mueller method that can be found on this forum with several search terms. Be careful when sticking fingers into the joints because there
is always the possibility of metal shards under the dust boot.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

 

[billvv]

Thanks for the suggestions...

I'm not sure how a bad tire/wheel would present 'bumps' only when holding the steering wheel to the left but not when going straight down the road.

I'm surprised that feeling the roughness when turning left would point to the left (drivers side) components. I would have thought that the PS CV
joint or tire/wheel would be the one under more load and therefore transmit roughness. Assuming it's a CV joint, what is the progression of symptoms?

By the way, the 'bumps' are much slower than if they were generated at each rotation of the tire/wheel. 60mph = 88fps. Say wheel is 8' in
circumference for calculation simplicity; that would mean 11 rotations(bumps) per second. 'Bump' is 2-3 per second. FWIW.

Had a chance to buy a used 'true-track' at a swap meet last week and passed it up. Should have grabbed it!
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015; Since arrival: New HVAC blower, heat flap cable, headlight switch.

 

[robert mueller]

Bill,

You can check the whole steering system end to end using this procedure:

http://www.gmceast.com/technical/Mueller_Steering_Inspection_Guide.pdf

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Bill Van Vlack
Sent: Tuesday, October 18, 2016 4:34 AM
To: gmclist
Subject: [GMCnet] Bump felt through Steering Wheel

Driving down the road at 60 or so, I find myself correcting left and right due to - I think - tramlining since it tends to go away
on smooth roads.
But that's not the issue I'm concerned about....

When I correct back to the left, I feel bumps through the steering wheel while the wheel is held steady - meaning that there are no
bumps when turning
the wheel, but bumps when the wheel is held with the wheels pointed slightly left. Something like 10 bumps with the wheel held left
for 2-3 seconds.
Once in a while I think I notice a bump or two when steering to the right as well, but I can't be certain.

Prior to noticing this (although it may have been there since we acquired the coach a year ago), I'd corrected the lower steering
column/steering box
angle, cleaned and re-lubed the balls in the lower steering column CV joint (in place, didn't remove the balls), replaced the front
calipers with 80mm
(including grinding to fit), replaced the relay arm and drag link, and aligned toe-in to zero.

What can be causing this?
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator;
new owner a/o mid
November 2015; Since arrival: New HVAC blower, heat flap cable, headlight switch.

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Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[billvv]

Thanks, Jim!
I'll check them first. A few months ago I followed Rob's procedure (Thanks, Rob) and found a bad relay arm and drag link which I replaced. We haven't
traveled on interstates since I bought the coach last year and just noticed this 'bumping' on the recent trip down and back from Coos Bay, but it may
have always been there - or masked by the bad parts.

> Bill,
>
> You can check the whole steering system end to end using this procedure:
>
> http://www.gmceast.com/technical/Mueller_Steering_Inspection_Guide.pdf
>
> Regards,
> Rob M.
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426

--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015; Since arrival: New HVAC blower, heat flap cable, headlight switch.

 

[Kelvin]

> Driving down the road at 60 or so, I find myself correcting left and right due to - I think - tramlining since it tends to go away on smooth roads.
> But that's not the issue I'm concerned about....
>
> When I correct back to the left, I feel bumps through the steering wheel while the wheel is held steady - meaning that there are no bumps when turning
> the wheel, but bumps when the wheel is held with the wheels pointed slightly left. Something like 10 bumps with the wheel held left for 2-3 seconds.
> Once in a while I think I notice a bump or two when steering to the right as well, but I can't be certain.
>
> Prior to noticing this (although it may have been there since we acquired the coach a year ago), I'd corrected the lower steering column/steering box
> angle, cleaned and re-lubed the balls in the lower steering column CV joint (in place, didn't remove the balls), replaced the front calipers with 80mm
> (including grinding to fit), replaced the relay arm and drag link, and aligned toe-in to zero.
>
> What can be causing this?

Did that "blue" shaft got cleaned and lubed while you were doing the
Lower Steering Shaft rework? Steering box is tied to the frame.
Steering column (and wheel) is tied to the body. That splined shaft is
the only real interface that moves between the two and if it gets stuck
and it can do what you're describing. Maybe worse if slightly off-center.

http://www.gmcmhphotos.com/photos/miscellaneous/p8623.html

This happened to me. Might not be the same thing you're experiencing
but just throwing it out there.

Kelvin
'73 23' in Eugene, OR

 

[billvv]

Kelvin,
It certainly slipped in and out easily; just a little suction. Don't remember adding grease, but the grease it had seemed in good shape. No apparent
wear to the blue coating.

The bumps were present when the wheel was held steady while the wheels were turning to the left; no bumps while the steering wheel was moving from
straight to slightly left. Makes me think that something's loose rather than binding. I want to double check the shaft/box angle at some point, so
I'll check it again. I think I used lithium sailboat winch grease for the sliding shaft and moly for the CV balls.

Lots of great suggestions; thanks all and keep 'em coming!
--
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid
November 2015; Since arrival: New HVAC blower, heat flap cable, headlight switch.