I recently completed the rebuild of the hydraulic pump which powers the cooling fans on our '93 U280. The pump is original factory equipment, has been in service for 169,000 miles and 4030 hours, and has never been touched. Our coach has the "2 pump" setup, with completely separate hydraulic systems for the cooling fans and power steering. If your coach has this setup, and uses this particular pump, you may consider yourself lucky. Why? Because parts are readily available at relatively reasonable prices, and because the pump is mechanically simple and easily rebuilt by the average "shadetree mechanic" (describes me perfectly).
Symptoms which prompted the rebuild: constant and slowly increasing seepage of oil around the shaft, and (more troubling) a "wobble" in the drive pulley which caused the belt to move back and forth on the pulley. The crankshaft pulley which drives this pump is a 6-rib style, and uses (obviously) a 6-rib belt. However, for some reason the pulley on my pump is a 8-rib style. If the belt is not tracking perfectly, there is room on the pump pulley for it to jump back and forth one groove. This is what was happening, resulting in a loud "snapping" noise and premature wear of the belt. The pulley was not "loose" - I checked the mounting bolts - so I hoped the pulley wobble was being caused by either a worn shaft bearing (possible) or a bent shaft (unlikely).
Sources I used to learn about the V10 pump:
From the Eaton.com literature library:
http://www.eaton.com/ecm/groups/public/@pub/@eaton/@hyd/documents/content/pll_1570.pdf
http://www.eaton.com/ecm/groups/public/@pub/@eaton/@hyd/documents/content/pll_1572.pdf
From the internet (YouTube):
http://www.youtube.com/watch?v=wOqJor92r44
Photos below of original pump before removal:
Our pump was manufactured by Vickers (which is now part of Eaton), and is a vane type single stage pump. The model number is V10F 1S5T 1C10J 20. The stock number is 0-2136886-3. This pump is really quite simple in design, and can be totally "refreshed" by simply replacing the center "cartridge" section, along with a shaft seal, roller bearing and two O-rings. I was able to procure all the necessary parts from 2 sources.
From parts4pumps.com I purchased the following:
VI148423 (shaft bearing), VI923468 (Cartridge kit, 5 GPM), and VI923548 (seal kit). Total price including shipping was $196.86.
Parts for Vickers V10/V20 Vane Pumps (http://www.parts4pumps.com/store/page15.html)
Because I suspected the shaft might be damaged, I searched for a new one. I lucked out and found it on eBay for $38.40 (with free shipping). Availability varies - search "Vickers V10" on eBay to see what is currently for sale.
V10 Vane Pump Shaft Vickers Hydraulics 374338 | eBay (http://www.ebay.com/itm/110566669086)
I also purchased a selection of plugs that I used to plug the 4 hydraulic hoses as I removed them from the pump. This minimized the loss of oil and prevented entry of dirt. These are called Parker Flare adapter plugs. They are available from any hydraulic shop...about $20 total for all 4. The sizes I needed are listed below - your hose setup and sizes may be different.
03CP-4
03CP-8
03CP-10
03CP-16
Photos below of the items purchased for rebuild:
Disassembly of pump is quite simple. Watch the video and study the parts diagram (linked in post above) before you start. Tools required for the job are a socket wrench set and snap ring pliers. BE SURE you mark the outside of the case with a marker so you will remember how the parts go back together! The case end covers can be "clocked" in any of four positions, so you need to get it right, or the hose connections will not be pointing in the right direction. Also, take note of the position and direction of the arrows on the center "cartridge" section. These pumps can be set to rotate either clockwise or anti-clockwise. You must install the new replacement cartridge correctly, or else the pump will not...pump. I took many photos before the tear-down, so I had a good reference when reassembling. Be careful to keep everything very clean while pump is apart.
Photos below of disassembly:
1. Photo of complete disassembled pump parts group (except the rubber shaft seal, which is still inside the front cover):
2. Close-up of pulley mount design:
Assembly is simply the reverse order of photos above. The only possibly tricky part is installation of the new seal. I used a properly sized socket to drive the seal into place. As noted in the tech manual linked in 1st post, the seal must bottom against the shoulder when installed. If you decide to change out the shaft, you will have to press the new bearing onto the new shaft. Following a tip I found online, I heated the bearing under a heat lamp, and put the shaft in the freezer. This made it pretty easy to install the bearing. I used a piece of copper tubing to press the bearing in place. If you decide to tackle this project and have any questions, send me a PM or email for details.
Photos below show the reassembled pump. Note the marks on the case showing alignment of the end caps, and the different color of the new center cartridge section (a sure sign of a rebuilt pump).
After carefully cleaning the mounting plate, I bolted the refreshed pump into place. Connecting (and removing) the hoses is kinda messy - have a drain pan in place below the pump. I lost a little oil when I removed the pump, and some more when I hooked it back up - probably 2 quarts in all. After re-installation, I thoroughly degreased the pump and hoses.
I was very careful when installing the pulley, to insure it went on straight, and checked several times for correct alignment with the crank pulley. Since the old original bolts looked kinda rough, I used new cad plated grade 8 bolts (from Lowe's) on the pulley mount. Once the pulley was tight, I installed a fresh new belt.
Vane pumps are normally self-priming, as long as the supply oil line is unrestricted. On our coach, the pump is mounted below the oil reservoir, which is a good thing. This is called a "flooded inlet", where the pump supply line gravity feeds oil to the pump. I cranked the engine, and as soon as I saw good engine oil pressure, ran back to check the fans:
They were not turning. :o
Ran back up front, shut off the engine, went inside to consult my online references. Found a notation saying if the pump does not immediately prime, you might have to crack a fitting on the pressure side to bleed trapped air. Went back outside, loosened the hose fitting at the inlet of my foreward fan motor until some oil started to run out. Back in coach, started the engine. Ran back and checked fans - HALLELUJAH - they were now turning at normal speed! I tightened the connection at the fan motor, cleaned up the oil mess, and let the engine run until fully warmed up. No leaks or problems evident - the drive belt is tracking perfectly on the pump pulley. Shut down engine and topped off the oil reservoir. I have not gone for a drive yet, but I am optimistic that everything will work fine.
I will close this thread with a final report after a good test drive.
Chuck, good write up!
Chuck,
Thanks for the detailed write-up and abundant photos.
Great read Chuck, I have the same system on our 92. Thanks for taking the time to set this up. ( Good meeting you at the Q )
Very nice write up Chuck.
Super details and photos.
Should be a great help to someone attempting this repair.
Thanks--Jim
Howdy Chuck,
GREAT write-up, with details, links, references and photos!!!
Dave A
Fantastic write up. I am planning on doing one for the wheel seal replacement I just did. Hope mine is as informative as yours.
Mark
@Chuck Nice job. Thanks for taking the time to write it up! I know how much work that is. ^.^d
see ya
ken
The transverse radiator (2 fans) U300 uses 8 rib pulleys on the crank as well as the pump. The earlier U300 models with the vertical mounted radiators have only one fan and may have either a six or eight groove pulley on the crankshaft. The U280 will use the same pump pulley and close to the same large mount. The reason the belt jumps back and forth one groove is that the belt tensioner was never properly aligned at the Foretravel factory. If you check the three vertical angles of the crank pulley, the tensioner roller and the pump pulley, you will quickly see the tensioner roller is at a different angle. Anytime the tensioner roller is moving up and down, it's because the belt is trying to take a different path and different length many times each second. 90 percent of shops mistake the "jumping" as a faulty tensioner and replace it. The surface of the new tensioner will have a different coefficient of friction and the bouncing may stop for a while but this only masks the problem.
You can loosen the bolts on the large black pump/tensioner mount at the engine block, move it fore and aft so the belt is centered on the tensioner roller and then loosen the fasteners (2 or 4) on the pump and slide the pulley to make sure they are all in a row. The tensioner will probably have to be shimmed where it bolts to the mount so all vertical angles are the same. Easy to do as seen in photos on much older posts.
All the belt "jumping" will cause pump wear so the sooner the whole assembly is aligned, the longer it will last. A properly aligned assembly will not see any belt wear or tensioner roller movement of any consequence. If the pulley on the pump is not rusted to the shaft, the whole process can be done in 30 minutes.
Before a trip, take a 3/8" or 1/2" ratchet and move the tensioner up and out of the way releasing the belt and with the other hand, spin the idler roller to see if the bearing is dry or worn. The angle finder is available at any hardware store for about $5 and only takes a few seconds to compare the three angles with the coach parked at any angle.
I just replaced a 7 tooth belt on our RAV4 driving the alt, AC and water pump and after 170,000 miles, it showed no wear, only a few cracks. Rule of thumb is count the grooves on the belt and then look for cracks. The belt should have no more cracks than the number of gooves for each inch of it's length. 8 groove belt should not have more than 8 cracks per inch of it's length.
Pierce
Pierce,
Some excellent info - much appreciated.
I have just this minute returned from a 1-hour test drive, to check the results of my pump rebuild. I am pleased to report that the pump is, to the best of my knowledge, working perfectly. My fans are apparently turning as well or better than they did "before" the rebuild, as evidenced by a consistently "normal" water temperature reading. The drive belt to my pump is now tracking exactly as desired - there is no discernible fore and aft movement of the belt, and the tensioner roller is absolutely stable (zero jumping up and down). The "wobble" is gone from the pump pulley. Either replacing the pump shaft and bearing, or reinstalling the pulley on the new shaft, cured the pulley problem. Whichever it was, I'll take it! ^.^d
Write ups like this, with this much detail and excellent photos are priceless. Thanks for having the forethought to do this and taking the extra time and effort!
Dick
Agree! THIS is why Steve built Foreforums!