Own A Newmar With Electric Slide Outs... Read THIS!

[Rvlegaleagle]

I presume Newmar is well aware of this situation and from what I have read on here the fix is rather simple!

Someone posted "This is an off the shelf gear motor and would require a huge investment to redesign for the low volume singular use in this application. Due diligence of adding the bolt check to routine maintenance should not be an issue." which overlooks the obvious and the post that follows it!

The problem, as I see it, concerns beefing up the bracket, using larger bolts and adding 2 more. Now how hard can that be? A broken bracket is hardly "maintenance" and the fix of bringing in to replace is time consuming even if it is for free. Newmar is a good brand and they need to keep it that way Just saying.

[OverDo]

Neal - That's a great idea. I should have thought of that as every high load assembly we ship has the paint stripe to verify torque and for verification by the customer that everything has been checked. I will continue to check mine periodically with a torque wrench just for peace of mind.

Buly - Assuming the airplane engine is making 180 HP @ 2000 RPM the torque required is 470 ft/lb (5640 in. lbs.). Assuming the 6 bolt circle is 6" diameter then each bolt needs to clamp roughly 311 lbs. (5640 in/lbs. / 3" radius = 1880 lbs / 6 bolts = 313 lbs.) A single 1/2"-20 bolt @ 40 ft/lbs. torque has roughly 6600 lbs of clamp force so in this case each bolt a safety factor of roughly 20.

The slide motor controller on my Ventana is limited out at 20 amps. 20 amps @ 13.2 volts is 264 watts which equals 0.3 HP. 0.3 HP @ 1 RPM = 1575 ft/lbs (18,900 in./lbs.) of torque. (Assuming the pinion gear moving the slide is 1 RPM which should be close) Assuming the motor mount bolt circle is also 6" diameter (I haven't checked) then each bolt has to clamp around 1575 lbs. (18,900 lbs. / 3" radius / 4 bolts = 1575 lbs per bolt) (more than 5 times as much as the propeller above). If you cut the speed by 75% as at the end of cycle (against the stop rods or house flange) then the loads go up 4 times (6300 lbs per bolt). A single 3/8"-16 grade 8 bolt torqued to 35 ft/lbs lubed has about 7000 lbs. of clamp load so is safe by about 10%. Blue Loctite is considered a lube during assembly. The same bolt torqued to 30 ft.lbs. has around 6100 lbs of clamp force so is marginal at those values using these assumptions.


VP - Safety wired bolts will not back out of the hole but if they lose their clamp load in this case from the gearbox slipping then the gearbox can continue to rock back and forth allowing the gearbox mounting face and bracket to wear. So far flange headed grade 8 bolts, Nordlock washers, and blue loctite have cured the problem for me. My back is too used up and close vision not good enough to be able to correctly wire the gearbox bolts where they are located. Using a clicker torque wrench is much easier for me.

If you stop the travel just as the slide is fully in or out but not let the motor controller limit out on amps you will greatly reduce the stress on everything and extend the life of all of the parts. These motor homes and big trailers are really just big machines that require thought and skill to operate safely and efficiently.

These are fun discussions and your mileage may vary

[VP Chianese]

Originally Posted by OverDo

VP - Safety wired bolts will not back out of the hole but if they lose their clamp load in this case from the gearbox slipping then the gearbox can continue to rock back and forth allowing the gearbox mounting face and bracket to wear. So far flange headed grade 8 bolts, Nordlock washers, and blue loctite have cured the problem for me. My back is too used up and close vision not good enough to be able to correctly wire the gearbox bolts where they are located. Using a clicker torque wrench is much easier for me.

Vern,

My back is about the same shape as your it seems. My preference would have been the Tru-loc bolts but a 25 year old tech I know did the wire ties and he used Blue LocTite as well. I'm fairly sure they are not going any place.

The bracket bending is a bit different. My bolts were never loose and the bracket did flex enough for the paint to pop in the bend.

My guess is it was a bad batch of brackets as Newmar has used these for years. The bad news is "they break" the good news is that for the most part Newmar stands behind them.

You are correct they require some looking after. Ever see an airplane with 0 AD's? I marvel at the folks that think they are never going to break and they should be flawless.

[Buly]

Originally Posted by OverDo

Neal - That's a great idea. I should have thought of that as every high load assembly we ship has the paint stripe to verify torque and for verification by the customer that everything has been checked. I will continue to check mine periodically with a torque wrench just for peace of mind.

Buly - Assuming the airplane engine is making 180 HP @ 2000 RPM the torque required is 470 ft/lb (5640 in. lbs.). Assuming the 6 bolt circle is 6" diameter then each bolt needs to clamp roughly 311 lbs. (5640 in/lbs. / 3" radius = 1880 lbs / 6 bolts = 313 lbs.) A single 1/2"-20 bolt @ 40 ft/lbs. torque has roughly 6600 lbs of clamp force so in this case each bolt a safety factor of roughly 20.

The slide motor controller on my Ventana is limited out at 20 amps. 20 amps @ 13.2 volts is 264 watts which equals 0.3 HP. 0.3 HP @ 1 RPM = 1575 ft/lbs (18,900 in./lbs.) of torque. (Assuming the pinion gear moving the slide is 1 RPM which should be close) Assuming the motor mount bolt circle is also 6" diameter (I haven't checked) then each bolt has to clamp around 1575 lbs. (18,900 lbs. / 3" radius / 4 bolts = 1575 lbs per bolt) (more than 5 times as much as the propeller above). If you cut the speed by 75% as at the end of cycle (against the stop rods or house flange) then the loads go up 4 times (6300 lbs per bolt). A single 3/8"-16 grade 8 bolt torqued to 35 ft/lbs lubed has about 7000 lbs. of clamp load so is safe by about 10%. Blue Loctite is considered a lube during assembly. The same bolt torqued to 30 ft.lbs. has around 6100 lbs of clamp force so is marginal at those values using these assumptions.


VP - Safety wired bolts will not back out of the hole but if they lose their clamp load in this case from the gearbox slipping then the gearbox can continue to rock back and forth allowing the gearbox mounting face and bracket to wear. So far flange headed grade 8 bolts, Nordlock washers, and blue loctite have cured the problem for me. My back is too used up and close vision not good enough to be able to correctly wire the gearbox bolts where they are located. Using a clicker torque wrench is much easier for me.

If you stop the travel just as the slide is fully in or out but not let the motor controller limit out on amps you will greatly reduce the stress on everything and extend the life of all of the parts. These motor homes and big trailers are really just big machines that require thought and skill to operate safely and efficiently.

These are fun discussions and your mileage may vary

My only concern is stripping the aluminum threads in the motor housing with 30 ft pounds of torque? That would be a big job to fix

[NealC]

I was under my coach today changing the Onan oil/filter and noticed orange strips on the bolts in the wheel areas. Looks like they do that for those bolts. I'm going to put lines on mine.

[OverDo]

VP - The bracket bending is a whole different issue that I have not had any experience with. The brackets on my Ventana seem like they may be an improved version by comparing to photos in this thread. I am considering making some gusset plates and having them welded in but as of now everything seems OK there.

Buly,
I used the longest bolt that would work (1" or 1-1/4" - don't remember which one) - and they torqued up at 35 ft./ lbs. with no problem. They felt nice and solid at that torque and did not show any signs of pulling the threads out of the aluminum housing. The key in soft materials is to use as much thread engagement as possible to lessen the load per thread but you have to check to make sure they don't bottom out in the hole.

[OverDo]

VP - The bracket bending is a whole different issue that I have not had any experience with. The brackets on my Ventana seem like they may be an improved version by comparing to photos in this thread. I am considering making some gusset plates and having them welded in but as of now everything seems OK there.

Buly,
I used the longest grade 8 flange headed bolt that would work (1" or 1-1/4" - don't remember which one) - and they torqued up at 35 ft./ lbs. with no problem. They felt nice and solid at that torque and did not show any signs of pulling the threads out of the aluminum housing. The key in soft materials is to use as much thread engagement as possible to lessen the load per thread but you have to check to make sure they don't bottom out in the hole.

[HavingABlast]

Some time ago I checked and tightened the bolt on my FWS and galley. Most were tight, but some needed snugging. I didn't do the Bedroom slide at that time, nor did I know about the recommended of blue locktite.

Fast forward to today. I purchased some blue locktite and borrowed a friends torque wrench. I pushed out the bedroom slide and popped open the two hatches on the right side under the bed. After some serious grunting and gymnastics (nothing showing but my big butt, elbows, and the soles of my feet) I sort of had access to the four large bolts that that were on the Non motor side of the plate. Most of these were fairly loose. I pulled each one out, one at a time then added locktite and snugged them up. Since they were 1/2", not 9/16th, I didn't go to the 33 ft lb spec. So for this old fat guy, It took me WAY more time than the 1/2 hr stated on the TSB for just these four bolts. I even took a 10 minute break after three bolts. I had to call it a day after that. Dinner called. Advil is in my future tonight.

For those that have done it, do you have to pull off the hatch on the other side of the bed in order to find the motor mount bolts (5/16" ?) and the torx bolts? Did you disconnect the piston things that hold the bed up? Did you completely remove the bolts, locktite them and remove, or did you back them out most of the way then apply the locktite, then snug them up?

I will tackle these tomorrow, along with the more easily accessible FWS and Galley slides.

[Rvlegaleagle]

Be curious to see how you made out and if anyone will answer your questions Keep us posted!

[OverDo]

Here is link to a nice recommended bolt torque chart. Grade 5 has 3 marks on the head and grade 8 has 6 marks on the head FYI.

Suggested Tightening Torque

[VP Chianese]

Originally Posted by HavingABlast

For those that have done it, do you have to pull off the hatch on the other side of the bed in order to find the motor mount bolts (5/16" ?) and the torx bolts? Did you disconnect the piston things that hold the bed up? Did you completely remove the bolts, locktite them and remove, or did you back them out most of the way then apply the locktite, then snug them up?

I will tackle these tomorrow, along with the more easily accessible FWS and Galley slides.

The bedroom slide motor is smaller than the large slides. The four bolts that you did LocTite are the motor bolts. You are done there.

The correct way is to remove the bolts one at a time, all the way, put a little drop of LocTite on the threads of the bolt and replace the bolts. More is not better. LocTite works on the principle of "lack of O2" When the bolt is threaded in and the LocTite is compressed between the threads the lack of O2 sets the LocTite off like kicker does to Epoxy.

[HavingABlast]

My thanks to the responders. After removing the under bed access panels I found that the motor was somewhat different than the others. There were no additional bolts to tighten. I will post a picture.

I completed the R&R plus adding locktight to the galley slide motor case, or is it a gearbox? The motor itself does not have the exposed two bolt that I've seen pictured. Instead there appears to be a cap over it that is banded on. I didn't remove the band, not knowing it I could get it back on. What is the correct process for getting to the bolts that hold the motor onto the gear box?

Here is the backside of the bedroom slide motor in case someone else (I know that I am a late arrival to this process) is doing the same PM.

[Dan McMartin]

Originally Posted by NealC

I was under my coach today changing the Onan oil/filter and noticed orange strips on the bolts in the wheel areas. Looks like they do that for those bolts. I'm going to put lines on mine.

The bolts on my Jeep's control arms have to be torqued to 125 ft lbs. If they loosen, the bolt holes in the brackets can become elongated and I could develop handling problems or death wobble. I changed the bolts to grade 8 shouldered bolts and torqued them accordingling (no small feet torquing to 125 lbs under a Jeep ).

Anyway, I marked them with Sharpie paint pens so I could see if there was movement. One line on the bolt head and another on the bracket. I can check at a glance to see if anything has moved or shifted and the paint has been there for three years. Beats crawling under there to check torque on 16 bolts with a torque wrench

[VP Chianese]

Originally Posted by HavingABlast

My thanks to the responders. After removing the under bed access panels I found that the motor was somewhat different than the others. There were no additional bolts to tighten. I will post a picture.

I completed the R&R plus adding locktight to the galley slide motor case, or is it a gearbox? The motor itself does not have the exposed two bolt that I've seen pictured. Instead there appears to be a cap over it that is banded on. I didn't remove the band, not knowing it I could get it back on. What is the correct process for getting to the bolts that hold the motor onto the gear box?

Here is the backside of the bedroom slide motor in case someone else (I know that I am a late arrival to this process) is doing the same PM.

Attachment 169033

Well that is the problem with answering questions here on the Forum. Sometime we answer a question and the facts are that the unit that the question is being asked about is totally different than the unit we are knowledgeable about. I can only vouch for the 2015 DS 4369. Now I believe the out side (under the floor in the compartments) motor and slide gearing is the same or somewhat the same on most of the coaches with electric slides. But the under the bed slide may be different.

From your picture I can't tell where you are under the bed. I can tell you that on the 4369 the bed slide is on the Starboard side aft. So in the bedroom looking at the bed from Port to Starboard with the bed up, the tunnel in down the center running port to starboard and the access is on the aft side of the tunnel. The four bolts are easily seen from there.

BTW I used Port and Starboard because everyone doesn't agree that the drivers side is the left and the passenger side is the right

I'm not sure what arrangement is on a 37' Ventana.

Hope this helps.