Does your Interstate shudder?

[kfrere]

Since picking up our 2016 Interstate last month I have taken it on 3 weekend trips - total about 700 driving miles. When I am braking, and the van gets down between 30-40 mph, I start to let up on the brake and the van shudders. It makes a noise, like a grinding noise, and it physically shakes a bit, then all of that goes away and it functions normally until I'm fully braked.

Yesterday, after contacting AS in JC, I took it to local Mercedes dealer to inspect. After 2 full days this is their response: "Once Airstream gets these they add a lot of weight. We couldn't find anything wrong. We did replace AC compressor. These vans will just normally do what you are experiencing."

First of all, I had no idea there was an AC problem. Sure didn't seem like one. But, have any of you experienced this? These vans are meant to be loaded down to carry cargo - I just didn't get that part. Should I follow up with AS on this or is this truly normal and not to worry?

[Protagonist]

You probably need a front-end alignment. Airstream doesn't do one after they do the conversion, so it's probably aligned for an empty van, not for its present curb weight or its present weight distribution.

My Interstate only shudders when a semi passes me and cuts back into my lane close enough to put me in his slipstream. The turbulent air coming off the back end of the trailer can be felt until he either pulls away or I back off to regain a more reasonable following distance.

[Ron_CA]

Not normal. The grinding noise is a concern for sure but should'nt shake either.

Mine is completely smooth when stopping

[73shark]

Since it's making a grinding noise, I suspect that it may be more than an alignment problem. I'm thinking it might be more like a wheel bearing going/gone bad.

If you do get an alignment, make sure they get as close to the zero side of the camber spec to prevent chewing up the outside of the front tires. It may take the special camber bolts to do this. MB should have these.

[Protagonist]

Originally Posted by 73shark

Since it's making a grinding noise, I suspect that it may be more than an alignment problem.

That is true, it could be more than just alignment.

But in the spirit of Troubleshooting Rule #1— Check the easy things first— front-end alignment is the easiest thing to check, and does no harm even if that proves not to be the actual, or only, problem.

Alignment is also something that can't be determined by plugging the van into the dealer's diagnostic computer, being a purely mechanical fault, not an electronic one. Any time the dealer says, "I can't find any problem," it's a good bet that the problem is either intermittent, non-electronic, or both.

[73shark]

Not sure how anything affected by alignment would cause a grinding noise but open to suggestions.

[Protagonist]

Originally Posted by 73shark

Not sure how anything affected by alignment would cause a grinding noise but open to suggestions.

Honestly I'm not sure either. But the OP reported TWO symptoms, a shuddering and a grinding noise. Faulty alignment definitely could cause the shuddering.

But you're right, faulty alignment probably wouldn't cause the grinding noise. Still, it's something easy to check, and considering the number of people here on the Forums who have reported excessive and uneven front tire wear, alignment is a common enough problem to be worth checking anyway.

But I'm not married to the idea, and if nothing is wrong with the alignment, it won't upset me at all to be told I'm wrong. The point is to help the OP, not to prove myself right.

If it is a wheel bearing going bad, the wheel(s) in question should get noticeably hot, so that's also easy to check without tools. Simply feel the wheel hubs after driving it for a while, and if one hub is notable hotter than the others, there you go. If there isn't a detectable difference in temperature, then back to the troubleshooting drawing board.

[73shark]

Warped rotor and/or pad sheared off.

[kfrere]

Thank you, guys. When I go in to MB this morning to pick up I'll cover these issues with them. Alignment, rotors, pads. I'll let you know what happens.



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[xrvr]

Older interstates had a driveshaft shudder on deceleration. Check the sprinter forums. Yours is newer but who knows.

[Mjgman]

A warped rotor like Shark said is most likely the culprit.... An easy way to check alignment is to get on a straight road and let go of the wheel if it is tracking okay it's most likely not the alignment... If the shudder and noise only happen when you brake then it is most likely the rotor.. Good luck.. Keep us posted..

[kfrere]

Okay. Picked up van at Mercedes. Said they checked "everything" but couldn't determine cause of problem. I requested that an alignment be done but they cannot do one because they don't have a rack sized to handle it. Recommended an alignment business but upon calling them they no longer take motorhomes. Then went to Travel America - don't do alignments but the very nice guy there called his buddy at Freightliner who said, sure, bring it over. Dropped it off. They say they, too, will check everything; that it should not be doing this. Asked me if it pulls to the side, I said no, guy said probably not alignment but they will do it anyway. No harm, no foul. May be a couple of days before they can get to it. When I get a final resolution I'll let you guys know the result.

Again, the feedback - and education - on this forum is incredible. Thank you!

[TomKirk]

The shaking, as you describe it, at precisely certain speeds, with relative consistency, is probably related to alignment. My bet is caster.

Think of the front wheel (that's not a true wheel, it's a "caster") on a grocery cart that "shakes" back and forth. It's a well-working "caster" on that makes the grocery cart roll forward in a (relatively) straight line.

If caster can't be adjusted, then something is bent. A good alignment tech at a medium duty truck shop will notice that immediately.

Tom

[kfrere]

I was told that there are 6 true Sprinter van techs in the entire state of Tennessee, and that one of them is at this Freightliner facility. Hopefully, that will count for something in this inspection/work.

[Lily&Me]

As new as your Interstate is, I would think all this should be under warranty, correct?

Mine has never shuddered, and I have never heard nor read of that with any Class B......but, we had a 77 Barth before our Interstate, and when it began shuddering in Colorado the front end had gone out.

None of this should be happening with a new rig, it doesn't sound like to me, and I hope you address these things under warranty rather than out of your own pocket.

Keep us posted.


Maggie

[clarklaflare]

Originally Posted by kfrere

When I am braking, and the van gets down between 30-40 mph, I start to let up on the brake and the van shudders. It makes a noise, like a grinding noise, and it physically shakes a bit, then all of that goes away and it functions normally until I'm fully braked.

I'll propose something completely different than others have suggested. Bear with me:

The next time this happens as you've described, try to immediately repeat it. But, instead of using the brakes to slow your speed, just allow the van to coast without touching the brakes until you reach the targeted 30-40 miles per hour.

If and when the symptoms reoccur, immediately (you'll have to be quick) bump the gear shift lever to the left (D-) one time to manually downshift the transmission to 4th. At this point, if the shuddering stops, you'll know the issue is not brake or alignment related and most likely related to the transmission torque converter.

It's hard to say if there's a legitimate problem or just that the operating conditions during the usual occurrence are such that the torque converter is in a partial unlock state when the transmission begins to automatically downshift from 5th. I have on occasion noticed something similar with my 3500 Sprinter when towing a loaded car hauler.

The "grinding" noise is difficult to interpret without actually experiencing it, but may just be drive-line noise as a reaction to the shuttering. It seems to me that if the problem was actually a mechanical grinding and something with the brakes, alignment, or wheel bearings, there would be obvious external evidence of the problem. Any vehicle mechanic should be able to see it.

If the diagnosis I've suggested pans out, I'd suggest explaining the results to an MB Sprinter dealer and try to get them to not blow you off. From the sounds of your prior experience, this may require a trip to Nashville, ???, or a call to MB Customer Assistance.

Good luck and let us know how you make out.

[Wolf Alaska]

Originally Posted by kfrere

Since picking up our 2016 Interstate last month I have taken it on 3 weekend trips - total about 700 driving miles. When I am braking, and the van gets down between 30-40 mph, I start to let up on the brake and the van shudders. It makes a noise, like a grinding noise, and it physically shakes a bit, then all of that goes away and it functions normally until I'm fully braked.

I have owned Class B vans since 1982. Your van is not broken in yet. Engine, tranny, suspension all needto wear in. You may be going to dealer a bit soon. Warrenty is long.

I have found heavy vans can't be driven like a light car. Get the engine up in power band in EACH gear when gaining speed. You can't get into OD then gain speed like in a little car.

Brakes are different, too. If you apply light pedal pressure you will feel the rotors as a vibration. Use a firm pedal pressure. If you don't need firm pressure, get OFF the brakes.

Don't lay your foot on the brake pedal & lightly slow down like you do in a small car.
Big van brakes want to be hot and feel a heavy foot.

Ignore this advice & you will feel shaky braking & spend lots of time in the shop, but nothing will ever get better.

Sir, you now have a truck. It will be rough and it should be driven like the truck it is.

You may have some mechanical issue but it will out itself in a few thousand miles. Drive your van like a truck & these issues may very well just go away by driving.

I recommend a quick coast to coast trip !
Let's Roll !
Wolf

[Wolf Alaska]

Originally Posted by Protagonist

You probably need a front-end alignment. Airstream doesn't do one after they do the conversion, so it's probably aligned for an empty van, not for its present curb weight or its present weight distribution.

Protagonist makes a good point. Often, the conversion mfg. does not align after building the van into a Class B. I don't know the A/S or dealer policy on this.

My new Coach House had a placard stating that the owner should get the MC aligned. My local Ford dealer's truck dept. set the camber with shims & it has been perfect for 18 years. Coach House reimbursed the alignment's cost.

The alignment likely has nothing to do with your complaint, but it needs to be done anyway.
Let's Roll !
Wolf

[kfrere]

Update: Freightliner called to tell me that they have not yet done alignment but have done the "transmission software update" that was needed. Like the AC compressor another thing I wasn't expecting. Wonder if that can somehow be related to my shudder problem.



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[Airline]

Could anyone imagine spending $150k on a New Vehicle that is out of alignment ?

And they don't tell you its out of alignment,so every mile you drive is prematurely wearing out your very expensive tires?

???