[GMCnet] Shock Absorbers

[D C _Mac_ Macdonald]

What is the recommended brand for our coaches?
I need to get new shocks for my 1999 GMC Sierra
at 188,000 or so miles and figure what's good for
our coaches is probably good in general.

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com
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[John R. Lebetski]

Since there are only 2 brands of shocks available for a TZE and lots available for your truck, probably not a good comparison.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[John Wright]

The 2 brands of shocks that are made for GMC Motorhome are the Bilstein and
KYB.

Bilstein part numbers - front Rear 24-213004

KYB part numbers - Front KG5435 Rear KG5436

I have run both, but the KYB's are the choice of most. Go to Amazon.com
and ebay.

J.R. Wright
GMC Great Laker
GMCGL Tech Editor
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 29.5' Stretch
75 Avion (Under going Frame up Restoration)



On Fri, Oct 8, 2021 at 8:21 PM John R. Lebetski <gransp...@gmail.com>
wrote:

[Jim Kanomata]

Thanks John.

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502

[Dave King]

Re non GMC MH shocks as asked by person who started this thread.
As you have an older vehicle I'm not going to suggest something exotic and expensive.
A lot of people who use them seem happy with KYB. I would also suggest Bilstein although they can be
broken in the GMC application. Just what I think I know.
--
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada

[Jim Kanomata]

ke care.

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502

[Jim Kanomata]

After we sell off the Bilstein, we will not deal with them as they are the
worst people to deal with.
KYB has never given us any problems and are trouble free.

[Larry]

Here is a copy/paste of a post I did a while back on this issue. HTH.

In 2002 I brought my coach home from Houston. Among other things, I checked the shocks, and found all Bilstiens. Two were broken at the top ring. Two
were intact, but all of the oil had leaked out, so were nonfunctional. The last two were functional but near dead. On the advice of others on the net,
I bought kyb's. I have about 75K miles on them now and my only complaint is that the bushings in the mounting rings are too soft for the application,
especially the uppers. The rubber di-forms and actually squashes out of the ring; I have replaced all of the bushings with "Energy Suspension" 3/4"
Polyurethane hourglass shaped bushings, Part #9.8108. These bushings have held up for 8 or 10 years now without degrading. Unless kyb has responded to
other complaints relative to the bushings and corrected it with a harder material, I personally would put those Polyurethane bushing in new kyb's and
avoid this problem later. Other than that issue, the kyb's have preformed well for me and I'd buy them again. JMHO

--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

[James Hupy]

I have them, KYB's, on my 78 Royale. I installed them September, 2008.
Disconnected the fronts to install control arm bushings a couple of years
ago. The gas in the shocks was still quite evident. Those things are a
bitch to compress to reinstall them. I wound up using big tie wraps to hold
them compressed enough to reinstall. I have installed a whole bunch on
customers coaches, and never have encountered a shock failure. Not so with
Bilsteins. They break welds, lose their gasses, their bushings fail, too.
My vote is with KYB's.
Jim Hupy
Salem, Oregon

[Fred Hudspeth]

My experience with Bilstein shock absorbers is apparently an outlier with that of most GMCMh owners who have used them. I replaced the OEM shock absorbers with Bilsteins almost 30 years ago and more than 100K miles. I have experienced none of the breakage reported by many owners. There appears to be little change, if any, in ride control and static stability since new.

I HAVE had to change the shock absorber/trailing wheel/driver side twice due to leakage (it IS a hassle working with Bilstein warranty service). 'Have been unable to define the cause of the leakage at that location and none at the other locations.

I elected to use the Bilstein product on my GMCMh as they were the OEM shocks on my high performance German cars. I have never had to change the shocks on those cars, including one I bought new a couple of years before buying the GMCMh (I still have that car!).

My perception is that the KYB product is comparable in performance to that of Bilsteins (with none of the breakage reputation of the Bilsteins) - AND is less expensive. My favorable Bilstein experience notwithstanding, I recommend the KYB as the more practical shock absorber for the GMCMh for most owners.

Fred


Fred Hudspeth
1978 Royale (TZE 368V101335) - Tyler, TX
1982 Airstream Excella (motorhome) - Cooper Landing, Alaska

[John R. Lebetski]

I agree Fred. No problems with the Bilsteins. My theory is rear eye breakage may be from improper jacking sequence (not releasing air spring pressure
before lifting). I only know of KYBs from other applications. They are as a rule very stiff shocks. This gives good control and firm ride, but on
washboard surfaces can cause the tires to get skittish as they can’t respond fast enough to maintain tire patch contact. The TZE probably has enough
GVW for this not to be an issue. GM AC Delco partnered with Bilstein back in the day as Delco Bilstein. My 93 S15 Jimmy SLT with factory soft ride
package had these shocks

--
John Lebetski
Woodstock, IL
77 Eleganza II

[Matt Colie]

My experience with Bilsteins is almost parallel to Fred's with one big exception. Back in my car racing days, that was the only thing we would ever
run...
Yes, we would blow one up from time to time, but our local rep was good about it.

Chaumière came to us with the Odo just over 100 and complete set of Bilsteins. Before we got another 10K, one of the rears was leaking. When I took
it off, the gas charge was gone and so was the damping over part of the travel. I replaced that pair with KYB. A short time later another started
leaking and had lost its charge as well. So, I reinstalled the better of the two removed. Then another leaked. I bought a pair of KYB for that set
and another set for the front as I now had no remaining confidence in Bilstein. The newest of the KYB has about 50K on it and they are all doing just
fine.

I am afraid that I do not agree with all of the wrong jacking being an issue. Our rear shocks compress with the suspension unloading. As that
compression should be handled, it cannot be an excuse for breaking the mount off or starting a leak in my opinion as a automotive engineer for many
years.

Unlike some other concerns, I have no family for a direct connection to Bilstein, if I did I would have used it to my advantage.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

[Jim Kanomata]

KYB has improved the rubber mounts several years ago.
If you purchased the earlier ones, contact me, and I will replace them or
send you the Urethane bushings n/c,

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502

[Fred Hudspeth]

John,

Re your post below...

The LRR shock absorber eyelets never broke. The two shocks that I had Bilstein replace at that location just leaked fluid on my garage floor. The warranty hassle was the time Bilstein techs took (about a week) to conclude that the leakage qualified for replacement of the shock - both times.

My practice, apparently like yours, is to always deflate the air springs when doing any rear suspension service, including lubing the bogie pins (or doing anything otherwise under the coach).

It may be that the Bilstein breakage problem became chronic in versions later than the version I installed in 1993.

Fred

Fred Hudspeth
1978 Royale (TZE 368V101335) - Tyler, TX
1982 Airstream Excella (motorhome) - Cooper Landing, Alaska

Message: 5
Date: Mon, 15 Nov 2021 11:31:36 -0700
From: John R. Lebetski <gransp...@gmail.com>
Subject: [GMCnet] Re: Shock Absorbers
To: gmc...@list.gmcnet.org
Message-ID: <59bdb.6...@gmc.mybirdfeeder.net>
Content-Type: text/plain; charset="utf-8"

I agree Fred. No problems with the Bilsteins. My theory is rear eye breakage may be from improper jacking sequence (not releasing air spring pressure before lifting). I only know of KYBs from other applications. They are as a rule very stiff shocks. This gives good control and firm ride, but on washboard surfaces can cause the tires to get skittish as they can’t respond fast enough to maintain tire patch contact. The TZE probably has enough GVW for this not to be an issue. GM AC Delco partnered with Bilstein back in the day as Delco Bilstein. My 93 S15 Jimmy SLT with factory soft ride package had these shocks
--
John Lebetski
Woodstock, IL
77 Eleganza II

***************************

[John R. Lebetski]

Matt usually there is a formed “land” at the end of the rod where it ends before the eye. Hard to see with the dust sleeve in place but think of
a typical GM RWD front shock threaded upper. I can see where jamming that into the seal on compression would compromise the seal on end of tube.

--
John Lebetski
Woodstock, IL
77 Eleganza II

[Matt Colie]

JohnL455 wrote on Mon, 15 November 2021 14:59

> Matt usually there is a formed “land” at the end of the rod where it ends before the eye. Hard to see with the dust sleeve in place but think
> of a typical GM RWD front shock threaded upper. I can see where jamming that into the seal on compression would compromise the seal on end of tube.

John,

That is exactly the kind of issue that should be accounted for in the specific design. Mine that leaked had not been driven to full compression in
the time I owned them. As most shock absorbers do like in a world where the suspension can be counted on to be fully extended at some point, the
design for such a specific part should have accommodated that. KYB seems to have managed to do that.

Matt



--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

[Jim Kanomata]

It is the Dynamic force of running all the way low and going over a speed
bump at 20mph. Shock is over extended.
For some reason, the KYB stands the abuse.






Just by jacking it up cannot damage it .

On Mon, Nov 15, 2021 at 11:50 AM Fred Hudspeth <fbh...@sbcglobal.net>
wrote:

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502