[Andre]

Hopefully Monroe’s “Save a Squirrel” campaign doesn’t catch on like Jiffy Lube’s successful campaign to get us to change our oil every 3,000 miles. Road condition is probably the number one variable in how long your shocks are serviceable.

[Archived]

Off all the posts over the years that have had discussions about the life of components I don’t ever recall any that offered evidence or suggestions on the life of shocks. I know when I see oil on a shock the chances are very good the shock is bad.

If you decide to replace shocks I have also noticed the force required to collapse the used shock is often (but not always) much less than on the new shock, indicating the shock has outlived its usefulness. There have been many posts in which the writer replaced bad shocks and commented on how much better the coach rode and drove.

In reality the shocks on our coaches are there for one reason. They dampen bumps and limit rebounding. I do not know how our shocks are set up. I do not know if they are biased towards resisting compression and allowing extension, or resisting both or allowing compression while resisting extension. If we have no shocks, which is the equivalent of driving around with worn out shock absorbers our coach’s air bags are the only devices that will resist “bottoming out” when we hit a bump, and nothing will resist the rebound. If a coach is nose heavy for example poor shocks will allow it to either bottom out or experience greater suspension compression upon hitting a bump. The coach will also bob up and down to a greater extent with bad shocks.

But with the exception of very sudden turns and the resulting lean from the turn the shocks have nothing to do with how much a coach leans in turns. It would take a violent turn to make the amount of lean dependent upon the condition of the shocks. If there is a suspicion the coach is leaning to a greater extent that is controlled by a device called a sway bar which may be on the front only or on the front and rear. As our coaches lean the sway bar which is a steel bar or tube that runs crosswise twists to resist the lean. In response to a lean our coaches ride height valves come into play because as the coach leans the valves respond by increasing the air on the low side (outside of the turn) and decrease the air on the high side. That gets into another whole issue because some coaches such as Karl’s have instant acting ride height valves and older coaches such as my 97 pre-IFS had time delay ride height vavles so it is entirely possible if Karl is experiencing a greater tendency to lean he could have missing sway bar bushings which allow a lean to begin with no resistance from the sway bar, he could have bad or restricted air flow in a ride height valve, or he could have a perfect coach and the excessive leans are induced by roads with multiple curves, the frequency of which at the speed he drives them get out of sync with the inflation and deflation of air bags in response to the curves.

[Archived]

Karl,

I did mine last winter and I believe they were original, 16 years
and 175K miles. When I took them off, I could extend and collapse the
shock by hand. They did not have any oil leaks, but like Jon said,
that is a sign of a bad shock that needs replaced. I knew they needed
changed out because on roads with dips and humps, there was little
resistance when the shocks were extending, causing the bus to
porpoise. The air bags were the only thing absorbing the bumps and
the bus was squishy (technical term).

New shocks made a world of difference, but mine were for sure wore
out. Yours only having 50K, unless leaking, are probably good. Mine were only about 42 bucks apiece at Prevost, not an expensive project.

[Archived]

A good rule might be to take advantage of one service event to perform another. For example, if you change out air bags that is a good opportunity to change shocks, not because their life spans are equal, but because access to one also provides access to the other.

[Ken]

I will let you know if new shocks make a difference as I am getting mine changed out while here at Camp Prevost. I have noticed a bit more bounce after hitting a dip and this is the logical thing that would have changed as we used the coach more.

Since all the roads are in such nice shape all around the country…NOT…I think our suspension parts really get a work out these days!

[William]

no bumps, so I guess I am just imagining additional lean. It really isn’t significant, but does show the power of advertising, doesn’t it!?

[Roger]

Mark,

In the interest of educating us how about comparing the force required to collapse a new shock compared to the old, and to see if there is a difference between the force required to compress compared to the force required to extend.

I realize this is subjective but I think it would be a good indicator of how long we can expect shocks to last and if they dampen jounce in both directions or are biased towards one or the other.

[Archived]

I hate it when Jon knows so much more than the rest of us.

Thanks Jon

[Archived]

Jon: I will play with them and report back as to what I think. I know it will be subjective, but still may be of some value.

[Archived]

We just replaced our shocks with the factory ones from Prevost and we can’t believe the difference in the ride… one of the front shocks was leaking so we changed them all… no records that they were ever changed before.

It’s driving like a new bus… sorry we waited so long… thought about going with Koni’s but after talking to several people we were advised to go through Prevost with the factory recommenations. Very happy !!

[Archived]

Well, the the job is underway and so far, no leakers, but they are not smooth like the new ones, and both in and out force is less. The two old ones I looked at we’re jerky on the inward stroke, and one a little going out too.

I suspect a valve issue on at least this one. What do you guys think?

[Archived]

Hard to say. At slow speeds such as you generate by hand the valves which are spring loaded may not even come into play and the orfice might be all that controls the resistance.

Can’t explain why it catches and releases.

[William]

I am not sure either. It is hard to hold them and make them react, but the new ones are smoother in and out than the originals. None of the old ones were leaking oil FWIW.

[Edward & Sandy]

Tom,

CAPT MOGUL says that no one should have to replace their shocks with only 18K miles on them.

Sandy

[Archived]

18K, I don’t get it.