HK Trucking

Yesterday I happened to be doing a brake job and wheel seal replacement on a truck with 46k Meritor rears. Here are some photos of the things described in my previous post: Meritor wheel bearing adjusting / retaining nut. The tabs on each side are pushed in when the socket is placed on the nut, thereby unlocking the nut from the spindle and allowing it to turn. On top of the spindle is the ABS wheel speed sensor. Sometimes when reassembling the hub onto the spindle, the sensor gets pushed back slightly. Once the hub is on and the wheel bearings are adjusted, place a .005 feeler gauge between the sensor and the notched ring on the hub, and put your finger behind the sensor and push the sensor against the feeler gauge. Notice that there is an ABS sensor on the rearmost drive axle only. When reinstalling the hubs, make sure you put the correct hub (the one with the notched ring) on the axle with the ABS sensor. This hub has the notched ring which allows the ABS sensor to detect wheel speed.

The first thing you need to do is get the proper size socket to remove the bearing adjusting/ retaining nut. Meritor uses a nut with 2 lock tabs that are depressed & released when the proper size socket is applied to the nut. Trying to loosen the nut any other way will not work and will damage the locking mechanism causing possible wheel end separation in the future. Once you get past that little difference, the procedure to change a meritor wheel seal is the same as any other make of axle. Also, if the truck is 1998 or newer and has ABS, after you reinstall the hub, use a .005 feeler gauge to set the clearance between the ABS sensor and the hub. Frequently these get pushed away from the hub when reassembling, resulting in too large of a gap, which causes the sensor to not provide a signal to the ABS, resulting in inoperative ABS, and the ABS warning light on the dash will be on if you do not re set the sensor clearance..

I just re read the original post in this thread. That 300 plus engine is not designed to work with the 5 or 6 speed transmission with it's 900 RPM spread between gears. The 300 plus was designed to be used with a closer ratio transmission such as a TRTXL1070 12 speed or a 9, 13, or 18 speed in order to keep it in it's operating range. I noticed that your truck is an RLST 685. That would denote that it originally came with an ENDT675 237 HP Maxidyne engine. The root of this problem is an incompatible engine / transmission combination. Perhaps you could swap a pump and injectors from an ENDT676 285 Maxidyne onto your engine and that would give it the wider operating range needed to pull from 1200 to 2100 RPM, the way that 6 speed is set up.

BTW, that trans in the photo is a TRXL 107 or TRXL 1071 6 speed. I can see the shift rail for the compound on top of it.

4.17 would be the Mack ratio. The TRL107 5 speed is direct in 5th. That trans with 4.17 rears on 10:00 20 (or 11R22.5) rubber will give 62 MPH @ 2100 RPM. I had a few with the TRXL107 6 speed which is also direct in high gear and that's what the top speed was. When the speed limit got raised to 65, I raised the high RPM to 2300 to squeeze a little more out of em.

A lot also depends on what size rubber is on the truck. With 11:00 24's 8.24 was a common ratio used in conjunction with a TRQ7220 quad box, and would give about 52 to 54 MPH in 5th hi at 2100 RPM if I remember correctly. On 11:00 22's 7.49 was common, with a quad box it would also give 52 - 54 MPH at 2100 RPM. On 10:00 20's, 7.00 or 6.34 was commonly used with a quad box. As was mentioned earlier, if the truck previously had a gas engine, then the rear axle ratios will be much lower than what you want for a 673 or 711 diesel.

In my opinion you won't find a nicer sounding engine than a 237 with a straight pipe.

Yes, definitely! The following story has nothing to do with sleeve removal, but points out that the ground should always be as close as possible to the weld area. A company up the road from here found out the hard way about proper ground clamp placement when welding. Evidently somebody put the ground clamp in a place where it allowed current to flow thru the main bearings. This caused burning and pitting of the bearings and when they started the truck, several of the main bearings spun. Talk about expensive f--- ups! Sure glad it wasn't mine!!!!!!

Wrap the journal of the crank with wet rags, then wrap the rags with several layers of aluminum foil before welding on the sleeve. When the sleeve is out, remove the rags and wipe any moisture off the crank.

Rob, what I meant was that even if you were to go to Europe, I'll bet that percentage wise there are no where near as many 30 something Volvos still in daily use as there are 30 something Macks still working in the U.S.

I wonder how many Volvos of that era are still running? Probably not many.

You can remove the setscrews that hold the clutch fork to the 2 halves of the throwout shaft , pull the release lever out of the side of the bellhousing,push the other half of the shaft out the other side of the bellhousing (takes some effort, there's a welch plug in the outside of the bore), then remove the fork, spin the throwout bearing so the grease port is to the bottom where you can reach it, and do whatever is necessary to connect the grease hose again. I've done it a couple of times, usually the pipe nipple is broken off in the throwout bearing, so you have to remove the broken piece and put in a new one and reconnect the hose, then spin the bearing right side up and reassemble the fork to the shaft. No need to pull the transmission for this. Regarding the rattle when the clutch is disengaged, are you sure it's not just the normal rattle of the centerplate when there is no tension on it?

Hi Rob. The FA 600 series front axle is the heavy duty one that was used on the B80 series, and some heavy duty B61SX's Here are a couple examples: And for those who aren't familiar with the FA 522, here is an example: IMHO, these front axles don't look right unless the stock "Mack" stamped hub covers are used.

One other consideration on a restoration---- If you stay with the original grease setup, you can use the original "Mack" hub covers. A FA 522 or FA 600 series front axle looks much more appealing with the original hub covers vs the "oil type". That said, gear oil is a better lube for wheel bearings.

...for one of our members on this board who was severely injured in a road rage incident this week. b83sx (Bill) is currently in intensive care with severe injuries after being run over by a hit and run driver. Bill is my cousin, a real Mack fan and a hell of a good guy, he didn't deserve to have this happen.

How about building it as a quad, and use 2 camelback setups, and have 4 driving axles?

DM886.

I've never tried to separate the 2 rails of a rust spread double frame, but if I did, I would make double sure all fasteners from one end to the other are removed, then try to start from one end, maybe put a chisel between the 2 rails (in the vertical section) and hammer it in like a wedge to try to get it to start separating, then use something larger, like a wood splitting wedge once it starts coming apart. Just go easy, so the frame doesn't get distorted. I'm sure Matt Pfahl would have a method for doing this, perhaps he'll see this and chime in.

Now I'm thinking again. In 1988, didn't Mack use a vented cap on their fuel tanks? Did someone replace the cap on the driver's side tank with a non vented cap?

Glenn, I think your theory makes the most sense. The only thing I'm wondering is why, with that much pressure on return side of the system, those plastic return lines between the injectors and from the injectors to that return fitting on the pump haven't blown off? They're only a "slip on" fit. I had one of those pop off on one of my trucks once, and every drop of fuel that should have been returning to the tank was being pumped out onto the ground. What a mess!

I wouldn't recommend that. Try not to weld on a frame rail unless it's a repair for an already broken frame, a splice to lengthen a rail, or to weld a dump body hinge to the rear end of the frame.

Yes, It's on the engine side of the firewall on a CH, no it's not hard to replace, but just make damn sure you put all the air lines back on exactly as they were.

Not really. Volvo is using Eaton Fuller transmissions (at least in the US market), so they would have SAE flywheel housings to bolt up to those, same as for the Mack transmissions.

"Fixed" that post.

Amen. Been there, Fixed that.