[Rovernet] Diagnostic help please [SEC=UNCLASSIFIED]
Coombs, Michael MR
michael.coombs at defence.gov.au
Tue Feb 10 20:29:42 EST 2015
UNCLASSIFIED
Before doing any of that I would check the front mountings for the diff
torque tube. Sounds just like a loose (or no) bolt, when you drive there
is no noise because the tube and mount are held together, when you lift
off the tube rises and bangs the body work. Check both the bolt itself
and the two mount bolts plus the cross member bushes at the sides.
Michael
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Mr Michael Coombs
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Today's Topics:
1. Diagnostic help please (LANCE LA CERTE PSY D)
2. Re: Diagnostic help please (James Pile)
3. Re: Diagnostic help please (magnet at ican.net)
4. Re: Diagnostic help please (Fritz Rauschenberg)
5. Re: Diagnostic help please (Vern Klukas)
6. Re: Diagnostic help please (Ben Saunders)
7. Re: Diagnostic help please (Andrew Holland)
8. Re: Diagnostic help please (Scruggs Family)
----------------------------------------------------------------------
Message: 1
Date: Tue, 10 Feb 2015 11:36:22 -0700
From: LANCE LA CERTE PSY D <lacpsyd6 at msn.com>
To: Rovernet <rovernet at rovernet.org>
Subject: [Rovernet] Diagnostic help please
Message-ID: <BLU170-W28E47A2AAC003B0F8034F783240 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
1970 3500S P6B NADA
Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
Car has developed a thumping which appears to be coming from the rear of
the car. At speed it disappears, but instantly returns as soon as you
take your foot off the gas. I've had the car up on the lift and with
the rear end suspended and the transmission in neutral I can rotate the
rear wheels by rotating the propeller shaft, i.e., nothing seems to be
'sticking'. I also noticed the left rear caliper is not engaging (right
disc is hot to touch after drive, left is cold).
I would appreciate any help in how to diagnose this thumping (and if I'm
going to need to drop the differential to address the brake caliper.
Lance La Certe, Psy.D.
It is absurd to divide people into good and bad. People are either
charming or tedious.
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Message: 2
Date: Tue, 10 Feb 2015 14:03:08 -0500
From: James Pile <jpile1 at verizon.net>
To: LANCE LA CERTE PSY D <lacpsyd6 at msn.com>, Rovernet
<rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID: <E07A4790-2D57-4BBE-A993-F50A9C8CE97D at verizon.net>
Content-Type: text/plain; charset=us-ascii
An often-heard rear thump can come from a universal joint that's on it's
way out.With the car on a lift, "wiggle" (technical term) the tires to
discover any play, rather than sticking, in any of the ball joints.
That's the only rear thump I've experienced in the past 40+ years of
Rovering. But that's the obvious analysis. Perhaps there are other
owners that will give you alternative things to check, but your brief
description of the problem does fit the suspect ball joint. The rear
caliper is a whole different matter.
Good luck!
Jim Pile
On Feb 10, 2015, at 1:36 PM, LANCE LA CERTE PSY D via Rovernet wrote:
> 1970 3500S P6B NADA
> Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
> Car has developed a thumping which appears to be coming from the rear
of the car. At speed it disappears, but instantly returns as soon as
you take your foot off the gas. I've had the car up on the lift and
with the rear end suspended and the transmission in neutral I can rotate
the rear wheels by rotating the propeller shaft, i.e., nothing seems to
be 'sticking'. I also noticed the left rear caliper is not engaging
(right disc is hot to touch after drive, left is cold).
> I would appreciate any help in how to diagnose this thumping (and if
I'm going to need to drop the differential to address the brake caliper.
>
> Lance La Certe, Psy.D.
> It is absurd to divide people into good and bad. People are either
charming or tedious.
>
>
>
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> Rovernet at rovernet.org
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------------------------------
Message: 3
Date: Tue, 10 Feb 2015 14:17:47 -0500
From: "magnet at ican.net" <magnet at ican.net>
To: Rovernet <rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID: <54DA595B.8040708 at ican.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I second Jim's comment about a faulty half-shaft universal joint. Best
way to check is to jack the rear of the car up and support it under the
rear end of the trailing arms (beneath the shock absorber mounts). That
way the half shafts will be in approximately the same position as when
the car is on its wheels. Put the hand brake on and try to rotate the
back wheels. If all is well, there should be no play at all. If you
can feel some lost motion, get under and look to see if it's the inboard
or outboard universal that's causing the problem.
The issue with the rear brake could be an inoperative self-adjuster (a
not uncommon problem). As Jim says, that's a story in itself, and
regrettably, it will probably mean lowering the final drive to get the
caliper off.
Cheers,
-- Bill Daddis
On 10-Feb-15 2:03 PM, James Pile via Rovernet wrote:
> An often-heard rear thump can come from a universal joint that's on
it's way out.With the car on a lift, "wiggle" (technical term) the tires
to discover any play, rather than sticking, in any of the ball joints.
That's the only rear thump I've experienced in the past 40+ years of
Rovering. But that's the obvious analysis. Perhaps there are other
owners that will give you alternative things to check, but your brief
description of the problem does fit the suspect ball joint. The rear
caliper is a whole different matter.
>
> Good luck!
>
> Jim Pile
>
> On Feb 10, 2015, at 1:36 PM, LANCE LA CERTE PSY D via Rovernet wrote:
>
>> 1970 3500S P6B NADA
>> Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
>> Car has developed a thumping which appears to be coming from the rear
of the car. At speed it disappears, but instantly returns as soon as
you take your foot off the gas. I've had the car up on the lift and
with the rear end suspended and the transmission in neutral I can rotate
the rear wheels by rotating the propeller shaft, i.e., nothing seems to
be 'sticking'. I also noticed the left rear caliper is not engaging
(right disc is hot to touch after drive, left is cold).
>> I would appreciate any help in how to diagnose this thumping (and if
I'm going to need to drop the differential to address the brake caliper.
>>
>> Lance La Certe, Psy.D.
>> It is absurd to divide people into good and bad. People are either
charming or tedious.
>>
>>
>>
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------------------------------
Message: 4
Date: Tue, 10 Feb 2015 14:59:01 -0500 (GMT-05:00)
From: Fritz Rauschenberg <wfritz at mindspring.com>
To: James Pile <jpile1 at verizon.net>, Rovernet <rovernet at rovernet.org>,
LANCE LA CERTE PSY D <lacpsyd6 at msn.com>, Rovernet
<rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID:
<28751992.1423598345891.JavaMail.root at wamui-june.atl.sa.earthlink.net>
Content-Type: text/plain; charset=UTF-8
I would vote for the rear end on it's way out. I replaced mine twice
over the years-the fist time I thought it was the clutch until I got the
car in the air. You also probably have rear caliper problems. So it is a
great time to drop the rear end out of the car and do it all.
Fritz Rauschenberg
Atlanta
-----Original Message-----
>From: James Pile via Rovernet <rovernet at rovernet.org>
>Sent: Feb 10, 2015 2:03 PM
>To: LANCE LA CERTE PSY D <lacpsyd6 at msn.com>, Rovernet
><rovernet at rovernet.org>
>Subject: Re: [Rovernet] Diagnostic help please
>
>An often-heard rear thump can come from a universal joint that's on
it's way out.With the car on a lift, "wiggle" (technical term) the tires
to discover any play, rather than sticking, in any of the ball joints.
That's the only rear thump I've experienced in the past 40+ years of
Rovering. But that's the obvious analysis. Perhaps there are other
owners that will give you alternative things to check, but your brief
description of the problem does fit the suspect ball joint. The rear
caliper is a whole different matter.
>
> Good luck!
>
> Jim Pile
>
>On Feb 10, 2015, at 1:36 PM, LANCE LA CERTE PSY D via Rovernet wrote:
>
>> 1970 3500S P6B NADA
>> Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
>> Car has developed a thumping which appears to be coming from the rear
of the car. At speed it disappears, but instantly returns as soon as
you take your foot off the gas. I've had the car up on the lift and
with the rear end suspended and the transmission in neutral I can rotate
the rear wheels by rotating the propeller shaft, i.e., nothing seems to
be 'sticking'. I also noticed the left rear caliper is not engaging
(right disc is hot to touch after drive, left is cold).
>> I would appreciate any help in how to diagnose this thumping (and if
I'm going to need to drop the differential to address the brake caliper.
>>
>> Lance La Certe, Psy.D.
>> It is absurd to divide people into good and bad. People are either
charming or tedious.
>>
>>
>>
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>> scrubbed...
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>> 0210/2748705c/attachment.html>
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>> Rovernet at rovernet.org
>> http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
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------------------------------
Message: 5
Date: Tue, 10 Feb 2015 12:15:47 -0800
From: Vern Klukas <vern at inkspotco.com>
To: LANCE LA CERTE PSY D <lacpsyd6 at msn.com>, Rovernet
<rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID: <86247D6E-4F8F-4E7B-ADC6-C79F3DF1EDC1 at inkspotco.com>
Content-Type: text/plain; charset=us-ascii
Hi Lance
A bit more detail on the thumps please. Is it all the time, or just when
you get on and off the gas or brake, for a start?
Yours
Vern
> On Feb 10, 2015, at 10:36 AM, LANCE LA CERTE PSY D via Rovernet
<rovernet at rovernet.org> wrote:
>
> 1970 3500S P6B NADA
> Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
> Car has developed a thumping which appears to be coming from the rear
of the car. At speed it disappears, but instantly returns as soon as
you take your foot off the gas. I've had the car up on the lift and
with the rear end suspended and the transmission in neutral I can rotate
the rear wheels by rotating the propeller shaft, i.e., nothing seems to
be 'sticking'. I also noticed the left rear caliper is not engaging
(right disc is hot to touch after drive, left is cold).
> I would appreciate any help in how to diagnose this thumping (and if
I'm going to need to drop the differential to address the brake caliper.
>
> Lance La Certe, Psy.D.
> It is absurd to divide people into good and bad. People are either
charming or tedious.
>
>
>
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Inkspot Type & Design 250 864 5619 in at inkspotco.com
------------------------------
Message: 6
Date: Tue, 10 Feb 2015 18:03:28 -0500
From: Ben Saunders <bsaunders at firstva.com>
To: LANCE LA CERTE PSY D <lacpsyd6 at msn.com>, Rovernet
<rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID: <54DA8E40.3030102 at firstva.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Hi Lance,
Try loosening the caliper that is tight and see if that helps but also
check the rear axle bolts to make sure they are tight.
Ben
On 02/10/2015 01:36 PM, LANCE LA CERTE PSY D via Rovernet wrote:
> 1970 3500S P6B NADA
> Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
> Car has developed a thumping which appears to be coming from the rear
of the car. At speed it disappears, but instantly returns as soon as
you take your foot off the gas. I've had the car up on the lift and
with the rear end suspended and the transmission in neutral I can rotate
the rear wheels by rotating the propeller shaft, i.e., nothing seems to
be 'sticking'. I also noticed the left rear caliper is not engaging
(right disc is hot to touch after drive, left is cold).
> I would appreciate any help in how to diagnose this thumping (and if
I'm going to need to drop the differential to address the brake caliper.
>
> Lance La Certe, Psy.D.
> It is absurd to divide people into good and bad. People are either
charming or tedious.
>
>
>
> -------------- next part -------------- An HTML attachment was
> scrubbed...
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> <http://rovernet.org/pipermail/rovernet_rovernet.org/attachments/20150
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> Rovernet at rovernet.org
> http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
>
>
------------------------------
Message: 7
Date: Tue, 10 Feb 2015 23:31:44 +0000
From: Andrew Holland <Andrew_Holland at amp.com.au>
To: "magnet at ican.net" <magnet at ican.net>, Rovernet
<rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID:
<91299A46EA25D5498A4B2C8BD8FA9B44CCF5D9A6 at COSAMPMBXSYD05.ampcos.local>
Content-Type: text/plain; charset="us-ascii"
Hi from Australia,
It's also worth checking the read Bolt in the Gearbox, as I had a
similar noise in my 2000TC.
You will need to remove the Drive Shaft (just remove 4 bolts at each
end) , then check the large bolt in the rear of the Gearbox where the
Drive Shaft connects.
Hope this helps
Andrew Holland!
-----Original Message-----
From: Rovernet [mailto:rovernet-bounces at rovernet.org] On Behalf Of
magnet--- via Rovernet
Sent: Wednesday, 11 February 2015 6:18 AM
To: Rovernet
Subject: Re: [Rovernet] Diagnostic help please
I second Jim's comment about a faulty half-shaft universal joint. Best
way to check is to jack the rear of the car up and support it under the
rear end of the trailing arms (beneath the shock absorber mounts). That
way the half shafts will be in approximately the same position as when
the car is on its wheels. Put the hand brake on and try to rotate the
back wheels. If all is well, there should be no play at all. If you
can feel some lost motion, get under and look to see if it's the inboard
or outboard universal that's causing the problem.
The issue with the rear brake could be an inoperative self-adjuster (a
not uncommon problem). As Jim says, that's a story in itself, and
regrettably, it will probably mean lowering the final drive to get the
caliper off.
Cheers,
-- Bill Daddis
On 10-Feb-15 2:03 PM, James Pile via Rovernet wrote:
> An often-heard rear thump can come from a universal joint that's on
it's way out.With the car on a lift, "wiggle" (technical term) the tires
to discover any play, rather than sticking, in any of the ball joints.
That's the only rear thump I've experienced in the past 40+ years of
Rovering. But that's the obvious analysis. Perhaps there are other
owners that will give you alternative things to check, but your brief
description of the problem does fit the suspect ball joint. The rear
caliper is a whole different matter.
>
> Good luck!
>
> Jim Pile
>
> On Feb 10, 2015, at 1:36 PM, LANCE LA CERTE PSY D via Rovernet wrote:
>
>> 1970 3500S P6B NADA
>> Background----Rebuilt engine (2,000 miles total), rebuilt Borg-Warner
35, replaced differential (lower mileage, not rebuilt), rebuilt rear
brake calipers.
>> Car has developed a thumping which appears to be coming from the rear
of the car. At speed it disappears, but instantly returns as soon as
you take your foot off the gas. I've had the car up on the lift and
with the rear end suspended and the transmission in neutral I can rotate
the rear wheels by rotating the propeller shaft, i.e., nothing seems to
be 'sticking'. I also noticed the left rear caliper is not engaging
(right disc is hot to touch after drive, left is cold).
>> I would appreciate any help in how to diagnose this thumping (and if
I'm going to need to drop the differential to address the brake caliper.
>>
>> Lance La Certe, Psy.D.
>> It is absurd to divide people into good and bad. People are either
charming or tedious.
>>
>>
>>
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>> scrubbed...
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>> 20150210/2748705c/attachment.html>
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>> Rovernet at rovernet.org
>> http://rovernet.org/mailman/listinfo/rovernet_rovernet.org
>
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Message: 8
Date: Tue, 10 Feb 2015 19:44:45 -0500
From: "Scruggs Family" <gjkzscruggs at verizon.net>
To: "'Rovernet'" <rovernet at rovernet.org>
Subject: Re: [Rovernet] Diagnostic help please
Message-ID: <017001d04593$ef18bfb0$cd4a3f10$@net>
Content-Type: text/plain; charset=US-ASCII
In my 44 years of P6 ownership I've had three final drive failures and
they were all accompanied by an increasingly louder whining sound. I've
never had one go 'thump.' When I've had a thump it has been a failed
half-shaft U-joint... several of those. For my experience when you get
an OEM replacement U-joint you get one that strangely doesn't have a
zerk fitting and cannot be lubricated... so you are left with whatever
lubricant that may or may not have been injected at their point of
origin. When replacing half shaft U-joints I make a point of getting
aftermarket units... the same, I have been told, that early IRS
Corvettes use... that do have zerk fittings as they will last much
longer with occasional lubrication.
I am seriously considering replacing the U-joints in my half shafts with
CV joints as they do not have near the drag of a U-joint. Hand push a
P-6 and then any other 3,000lb car... I contend the extra 'weight' of
the P-6 is due to U-joint drag/resistance. May be costly to make the
change but it will amount to a horsepower increase with longer life.
And while you're in there have an aluminum /aluminium driveshaft made as
you will appreciate the weight reduction of the rotating mass.
When you pull the handbrake it ratchets the rear caliper pistons into
the pads to take up any slack. If the cable or the ratcheting mechanism
is out of adjustment then the pads on that side will eventually not
touch the rotor before the other side does. If your calipers are not
leaking then they are most likely victim of poor adjustment/maintenance
which can be addressed without dropping the differential. Yes, it's
tight up in there but for my experience dropping the differential is one
of the last things you want to do unless you have a lift and three
husky, amiable friends. Also check the top edge of the differential
mount for stress cracks while you're under there and weld or replace as
you choose. And tighten the panhard rod mounting hardware tighter than
factory specs so it won't shudder under cornering loads.
Gross Scruggs
Annapolis MD
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