November 2016

Snowcat Maintenance

A SAM roundtable discussion explores the practical, confounding, and sometimes comical world of vehicle maintenance.

Written by Tom Kendrick | 0 comment
Photo credit: Pisten Bully Photo credit: Pisten Bully

Snowcats are funny creatures. They meow, hum, purr, hack up a snowball now and then. Sometimes they shut down and take a nap. Sometimes a cat will dart left or right with no warning at all. It is the snowcat mechanic’s mission and desire to ensure that the cat purrs all the time, and to keep those other behaviors to a minimum.

The cat tech’s efforts aren’t the only variable in the system, however. The other responsible party for snowcat care is the operator. It’s a huge benefit, and a challenge, for operators to know what the techs know in order to keep the cat happy and purring.

To that end, I spoke with a few veteran snowcat techs to get some insight on things they’ve experienced in their years under the hood of these incredible machines. The goal was to get feedback that could be useful to any operator, other techs, or anyone interested in machinery in general.

Our Panel:

Mike Johnson: Canyons Village at Park City, Utah

Mel Uhl: Park City Mountain, Utah

Jeff Perry: Peterson Equipment Co./PistenBully

Jesse Gibson: Telluride, Colo., and GJ Prinoth

Tim Wright: Bear Creek, Pa.

Alex Ausseresses: Alta, Utah

I’ve been working on snowcats since the late-‘90s, and thought I’d seen it all. I was wrong.

You’ve seen, touched, fixed, and dealt with many things that a cat tech sees over and over again. Can you share some of the common pitfalls so that they can be avoided or managed?

Mike Johnson: You know for us, it’s things that are training issues and typically a result of cycles when we have higher turn over. Common issues I’ve seen are fluid levels over filled and lost/missing fuel caps. On PistenBullys, sometimes the blade won’t lift (float switch), cab/deck won’t lift (tiller raised), brake won’t release (cab lift hasn’t been reset to operating positions). On the Prinoth cats, the E-stop button on Beasts throws a plethora of diagnostic trouble codes.

Mel Uhl: I think the things we see frequently are hurried or inadequate checkouts, and operators who get in a hurry and bump things with the tiller.

Jeff Perry: Oh man...I can’t even tell you how many times I’ve rolled into a yard and had people ask me about a tiller that won’t run; makes one turn and then stops or bounces backward. Every time, it’s just because the quick couplers on the rear lift frame aren’t tight. And speaking of couplers, the other one I’ve seen over and over again is blown tiller motor seals from not draining tiller hoses for summer. You gotta pull that case drain coupler and tie a rag around the end of the hose for the summer or you’ll have a blown motor seal in the beginning of the season.

Jesse Gibson: Well, you know I think one of the common things that I’ve seen over the years is guys driving too fast, catching a blade wing on something solid or some hard snow and exploding a blade wing cylinder. We had one guy do three of those in one year! (laughs)

Alex Ausseresses: Issues caused by lack of operator training. You go through things with them, but how well do they retain stuff? Like on the PB; when you stop and set the brake, then resume grooming, the tiller isn’t running. You need to re-start the tiller. Guys forget and make pass after pass with the tiller off, totally clogged up with snow.

Every tech has encountered a unique, unusual, or obscure problem with a snow cat that takes them on a diagnostic journey. Recall one of these diagnostic adventures for us.

Mike: I had a BR350 that developed a problem where the engine would randomly die. It could go two minutes and die, or it could run for two weeks without any problem. Obviously, when it was running fine, it was hard to diagnose a problem that didn’t exist. After trying a number of things, I had an idea and pulled the sending unit from the fuel tank, looked inside—and there was a latex glove in fuel tank! It would randomly get sucked into the fuel pick up, then when the cat would die, it would float away.

How did a latex glove get into the fuel tank? The operator lost a fuel cap, then thought a mechanic’s latex glove would work. As the fuel was consumed, the glove was sucked into the tank and the troubles started.

Mel: These are fun to recall. We had one on a PistenBully where the tiller cutter bars locked up no matter what. We checked all the normal things, but it still wouldn’t go. I did a little checking around the shop and figured out that one of the guys had changed a seal on a drive motor. That was a clue. I checked and found that when re-assembling, they had crossed the hoses on that side, so the two motors were trying to turn the bars in opposite directions.

Another weird one we saw was a blade wing ram had a mind of it’s own—it would “wave” at you randomly. Turns out, the blade wing had hit something and bulged the ram body; oil was intermittently going around the piston and causing erratic operation.

Jeff: For a while, we started seeing HDP failures going through the roof on BR350s, but only at very select resorts. HDPs were “smoking”. If the operator rubbed his pants on the seat, then got up to exit the cat, a puff of smoke would rise from the HDP. The problem was static electricity generated by the operator on the seat was grounding through the HDP. I found this by grounding my meter to the HDP, holding the positive lead in my fingers, then rubbing my backside on the seat and then standing up off the seat. As soon as I left the seat, my meter spiked to 45v. That power was frying the HDP’s.

I also found an issue that was a lot like MJ’s with the glove, but I got a little sidetracked looking for the problem. The operator was convinced that it was a drive system/calibration issue. I tried calibrating the drive a couple times and kept getting the same complaint—that the cat had no power. Finally, in a conversation with the operator he said, “...right before the cat dies, it”—“Whoa, hold on a minute,” I said to the guy, “It DIES!? That’s not a drive system problem, that’s a fuel problem!”

After that I started going through and checking the fuel system. Ya know those red, plastic caps they install at the factory in all the ports and fittings? Someone must have just pushed them into the fuel tank during assembly rather than pulling them out. One of those plastic plugs was getting sucked up into the pick up tube. It had a tiny hole in it that would allow just enough fuel to run the engine most of the time, but not enough flow for the engine to create any power. It wasn’t a drive system problem.

Jesse: We had one with a PB where the blade function wires and seat heater wires were shorting together in the seat harness. For some reason, I’m not really sure why, but it would build up a charge and when the operator would push a blade function button he’d get a big shock through the button. Since the operator was a newer guy, he assumed that the problem was just static from his pants on the seat so he didn’t say anything for weeks. Eventually, the operator told the mechanics about the issue and showed his finger, which now had a blister from getting shocked so many times!

Tom Kendrick: I had one that was not only “obscure”, but for ME, it’s also “the one that got away.” In other words, I still haven’t figured it out, although I did fix it. I had a PB300 where two of the front blade functions didn’t work. I was able to quickly diagnose that power wasn’t getting to two of the magnets on the front blade frame, MV1 and MV2. I was able to quickly determine that there was power to the front grille. Bad harness from the grille, forward—easy, right?

I pulled the hydraulic hose sheathed, four-wire harness off the curl ram and pulled the wires from it, installed new wires, pins, connectors, put it back together...but no change. WTF? I started continuity testing the harness from the grille to the MV valves in every possible way -everything tested good and no shorts to ground, to the sheath body OR to other wires in that harness, but still, I got no power to those valves. How? Why?

I was finally able to prove that it was the hydraulic hose sheath; with all four wires removed from the sheath, but hooked up, the blade functioned normally. Inside the sheath, it wouldn’t work. I hypothesized that the sheath must have had a wire poking through I.D. and poking through the insulation of the inner wires. I got a new sheath/wire housing and installed the wires into it, hooked it up...same problem! I must have had that harness apart and together 10 more times and I could not get it to work with the wires inside the sheath.

I was ready to build my own front harness using split loom, but as a last ditch effort, rather than crimping the pins on the wire ends, I soldered the pins on the wires, then assembled the wires into the sheath (again)...and it worked. I don’t know why it worked that time. The solder? Why did the wires work previously, outside the sheath? I don’t know. A fellow tech who observed the whole ordeal claimed that perhaps I’m only “three-wire certified” and that was a four-wire harness. Maybe he’s right.

Tim Wright: I had a cat that would leak oil from the hydraulic tank...sometimes. It would only leak when it was above the full line...once it got below the full line, it would stop leaking on it’s own. Eventually, I found a hairline crack in the tank that was just about even with the full mark in the sight glass.

Alex: I had the same as MJ and JP, except with an earplug. Yeah, you could start the cat, rev it up in the shop, but as soon as you starting pushing snow it would fall on its face. After working on it for a while, I finally thought, “something is going on here,” and I pulled the sending unit out and found a little yellow earplug stuck in the fuel pick up.

Every good tech is always seeking the best/fastest/smartest way to do any project on a cat. Over the years, what tips/tricks/advice have you found to be especially helpful?

Mike: It really helps to have vehicle maintenance provide a portion of the training or pre-season orientation. In that training, you gotta provide the “why.”

Another thing we’ve started is we, the techs, are doing a pre-shift walk around every day. We find tons of stuff ahead of time by doing that.

When I’m working on cats, I try to keep some things in mind: Who was there last? What mechanic or person was working on a given part? KISS (Keep It Simple Stupid)—remember and review the basics before getting into the weird or unlikely problems. And pay attention to the symptoms, you know? What is the behavior? Seek out the root cause and avoid making assumptions.

Mel: We’ve spent a lot of time working out bugs with a bunch of little things...

Marking wheel bolts, torque hub bolts and those kinds of things. Then you can look quick and see if they’ve moved.

We’re using regular grease for the BR tiller box, and for us it’s worked great; doesn’t leak, no problems.

On PB torque hubs, throw away the Allen drain plugs and use hex head plugs (available from PB) that don’t strip.

We add angle iron skid plate under the engine on PB 400s.

We mark the front tires to see if the tire is moving on rim.

Once the bolt bushings get loose in the sprocket on a PB, the bolts will break off in the hub. Change the sprocket!

Jeff: On BR350s, I see some people struggling with bleeding the hydrostatic system after servicing or replacing parts; bleed the filter housing first. That is the most important thing to get done; otherwise you’re just fighting air in the system for the rest of the time you’re bleeding. So, do the filter housing first, then cooler, then the rest of the system and that will make things go a LOT better.

Jesse: I feel that techs need to do a better job of putting themselves in the operator’s shoes. Operators’ logs are confusing sometimes, but techs should ask themselves, “Why would that matter?” “What was this guy thinking?” or, “What was happening in the cat for him to write what he wrote on the log sheet?”

The other thing is: keep it real—we’re not working on an F1 car here.

Tom: When the BR350s came out, we saw an increase in engine displacement and technology. As a result, they had way more power and torque. But the drive system calibrations stayed about the same, so you can turn down the drive-away RPM and full stroke RPM in the drive ‘puter, then train the operators to run at the lowest RPM possible. You get improved fuel economy without impacting production, and a side benefit is less engine wear and stress.

Tim: Getting the operators to avoid wearing ear buds/headphones helps a lot! Hearing the machine is vital to preventing catastrophic failures.

Also, culturally, scaring and intimidating operators is old school. If the operators really wanted to damage machinery, they could do a lot worse. Once the operators know that we want the machines at 100 percent and we’re trying to do so, they reciprocate that and take better care of the machines.

Alex: Like MJ said, I’ll go back through the records and see what has been done. A lot of times, a problem occurs because of the work that’s previously been done. We can’t all be perfect.

Another bit of advice is take advantage of everyone having smart phones. I’ll tell operators, “Take a pic!” Whether it’s DTCs on the display screen or something on the cat itself, that information can really help us determine what is going on quickly. Many times it can be a “go ahead and run the cat” (not serious) type of problem.

What are some things operators do that make your job more difficult?

Mike: When I get to a cat that is not shoveled and not plugged in. An even worse one is when I hop in a cat and everything—I mean, EVERYTHING—is turned all the way up; stereo, speed pot, heater fan...oh man, that is irritating.

Mel: You know, I don’t want to say anything negative here and honestly I think they’re doing really well. I’ve been really impressed with them over the past few years.

Jeff: (said with a BIG smile) Everything operators do makes it more difficult, man. Everything.

Jesse: I think that when guys neglect to write something up for whatever reason, you know, letting something go until it turns into a bigger problem...that doesn’t really help at all.

Alex: Not being truthful. I had an operator come into the shop and tell me the tiller is not leaving a good pass, “pitch gauge isn’t working,” he said. Well, the gauge and function was working, but the operator had backed the tiller into a tree and bent it so the positioning was all wrong. It would have been nice if he’d mentioned that he backed into a tree!

The other thing is trying to decipher their logs. Between spelling, grammar, and words that aren’t real words...sometimes it takes all the mechanics in the shop to figure out what the ops are trying to say on their log.

Tom: I’m with some of the others; communication is crucial. When that is lacking or poor, it’s hard to do a good job in the shop. Help us help you. Also, they should be “engaged with the mechanism.” In other words, have a relationship with the machine.

Tim: Not informing mechanics of issues, even minor ones. A minor one today can be major tomorrow.

What can operators do to help make life easier and keep a cat running well?

Mel: Feedback when there’s a problem and describe all the nuances when the problem is happening. Pay attention to little details on the machine: when the cat is running hot, if they notice the fan clutch only coming on at low speed, etc. Watch engine temps, don’t push too hard, and be gentle. Running hard is faster, but then you need to fuel up more often, which takes time. Know the idiosyncrasies of your machine. And finally, always ask questions of the mechanics.

Jesse: Well, like the electrical with the joystick, pay attention to when it happens. Being able to tell mechanics details like that can make a big difference. Keeping the cats clean helps, too.

For the mechanics, I think doing a daily inspection, walk around, and look at things as much as possible. Melt out cats whenever possible, and you know...put an eyeball on stuff. Steamboat is a good example; they have awesome up time because they put the cats up on the lift and melt out every cat, every day.

I also think it helps when the operator understands the machine’s capabilities, as well as its limitations.

“It also helps if the operators are a little persistent with the mechanics with concerns about the machines. Sometimes mechanics are a stubborn breed; we don’t always believe the operator for some reason, so if a concern is real, be persistent with the mechanic.” — Tim Wright

Tom: As I mentioned earlier, have a relationship with the machine. If you have that, then you know almost instantly when things are starting to go wrong. Sounds, smells, feel—everything tells a story about the machine. As an example, I’m sure every operator has noticed that cats have intermittent smells: oil, hydro, coolant after a hard climb sometimes. Once I was coming down off the hill, following another cat. I got a whiff of gear oil, but dismissed it as normal. But then I caught another whiff of it. And another. Something wasn’t right. I called to the operator ahead of me to stop. We jumped out and I started looking at his cat—there was a drain plug missing from the left torque hub. That hub, and several thousand dollars, was saved because of a smell.

Tim: The most helpful thing I think is for operators to do a good pre-check. It also helps if the operators are a little persistent with the mechanics with concerns about the machines. Sometimes mechanics are a stubborn breed; we don’t always believe the operator for some reason, so if a concern is real, be persistent with the mechanic.

Alex: This is where experience comes into play. The guys who have been there a while know how the cat is supposed to run and they’ll pick up on things before it becomes a big problem.

Tell me about something you’ve seen or experienced in your years as a mechanic that gave you a good laugh.

Mike: Oh logs are a riot! You name it: grammar, spelling, math (cats lose hours one shift to the next), and terminology (“wing” instead of “Dumbo ear”). One that sticks out in my mind is a log that simply stated, “Heater is hot.” Um, yeah. Isn't it supposed to be?

Mel: We had a rookie who was on a mission to install shovel holders on an LMC. He had steel brackets for the shovels and he started trying to weld them to the LMC’s bed, which is aluminum. He worked at it SO HARD, he got one metal to melt and flow around the other, and it worked! It was incredible! Simply because the guy was so inexperienced that he didn’t know it wouldn’t work, he made it work.

Jeff: This one time I had to go out and fix a cat that had lost a pump drive coupler. I got all the pumps out, and another tech showed up to help me. Sun was out, it was a nice mild day so he volunteered to dig a pit and climb underneath the cat to put the thing back under there. So he threw on his coveralls, dug the pit, slid underneath the cat and started working.

Between all his digging and wrenching under the cat, he worked up a substantial sweat. As we were finishing up the job, the sun was going down and it started to get cold. I mean...really cold. So cold we were worried about our own body temps and worked as fast as we could to get done and get out of there.

As we wrapped it up, it was time for my partner to slide out from under the cat, but he couldn’t. He was stuck. So I had a look under the cat to see what he was hung up on and, dude...he froze himself to the ground. I guess with all his body heat and sweat from earlier in the day, and then the plummeting temps, he had frozen himself to the ground! You know the little kid in the movie “A Christmas Story?” It took me a solid half-hour to break him free and get him out from under the cat.

Jesse: A guy came in complaining that the tiller was leaving a bad pass. A quick look at the cat and it the problem was obvious—the rear lift frame was broken and the tiller was being drug along by the hoses.

Another time, an operator was pulling into the snow covered, gravel cat yard with the Zaugg pipe cutter on the front of his cat. He thought he’d be super cool and turn on the Zaugg to shoot some snow at the guys fueling their cats. In the process of showering snow on them, the Zaugg picked up a rock and shot it over the shop, putting it through the windshield of a company truck.

Tom: I had a cat down on the hill with a Detroit Series 40 engine that had a broken idler pulley bracket. I called up on-hill to a patroller (who was a self-proclaimed snow cat mechanic) and asked him to get the serial number off the engine for me. He called back when he was at the cat, “where is the serial number?” The cab was already tilted so I told him to stand on the tracks and look straight down at the top of the motor. On top of the motor is the valve cover, right on top of that, facing straight up, is a tin plate with the serial number stamped into it. I need that number off that plate that is on top of the motor. He couldn’t find it, couldn’t find it, didn’t know what the valve cover was. We talked back and forth, and finally he came over the radio, “I found it! It’s right next to the spark plugs!” Yes. Good job. Right next to the spark plugs. Now, what is the serial number, please?

Tim: We had an operator come into the shop complaining that the tiller stopped working halfway through the night. We brought the cat inside and as we were curling the tiller up to have a look underneath it and we found the problem. The engine side panel was mangled and stuck in the tiller. We later told the operator what we had found and asked him if he noticed his engine side panel was missing. He said, “Nah. I wonder when that happened?”

Alex: We had an operator who was really green, and didn’t know the difference between the radiator cap and the oil cap. So this one time, after he had been doing fluids he said to us, “I had to put like six or seven gallons in there!” I said, “WHAT!? Show me.” He pointed to the oil cap (3700 AC) at the front of the valve cover, where he had filled the entire engine with coolant.