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Posted (edited)

Long time since posting! And this time it's about a Mack :) I'm looking at buying a used 1990 Mack MS series Midliner locally, I'll be going to have a look in person tomorrow. I understand these are Renault-built trucks and that parts can be hard to find, but that they generally last a good long while if maintained well. This one's got 183K on the odometer, so as long as it's not been abused, I think it stands a good chance of being useful to me. What I know about it:

* Air brakes (I can see chambers on the rear axle)

* Owner reports it starts well in the cold (not that we have real cold in VA!)

* 5-speed manual transmission

* Inline 6 Renault turbodiesel

* 25K GVW

The big question currently is, in what year did Renault/Mack ditch the air-over-hydraulic system on Midliners? I've read that it can cause real issues and be very expensive to repair if it wasn't maintained on a schedule. I'd prefer full air brakes, but I'm guessing it's not worth trying to convert a truck with air-over-hydraulic.

Second, is the 5-speed likely to have overdrive for this year?

Edited by glitchwrks

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That would be an MS-250 w/air over hydaulic brakes and they are VERY expensive to maintain/repair. I would pass on the truck over this setup myself. The full air brake trucks, (MS/CS-300 series were very reliable minus the Renault air compressor mounted far too close to the exhaust pipe in the CS-300 series baking the compressor head and causing valve problems, (IMO) which were usually sticking open valves precluding pressure buildup.

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Any idea on the service intervals on the air-over-hydraulic system? I likely wouldn't be putting a ton of miles on it and I don't mind doing regular maintenance on equipment. Anything to look for in specific as to telling whether it's been abused?

Any idea how similar or not the Renault system is to the system on M35 deuce and a half trucks? That's the only "air over hydraulic" I've had to mess with. Also not a fan :)

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200 series had air rear brakes and hyd front with light axles

250 had air front and rear brakes with mid weight axles

300 had air front and rear brakes with heavier axles.

From what I recall in the 90s models for both MS and CS midliners

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Went and looked at it today, it's hydraulic front disc brakes and what looks like regular air rear drums. Seems to have maxi/spring parking brakes. From looking it over briefly, I can't tell if it's got a master cylinder at the pedal or an air foot valve -- I didn't really dig into it. There's a brake fluid reservoir down on the air booster, unlike the M35 deuce and a half boosters which take their fluid from the master cylinder reservoir. Is this just air servo control for the hydraulic front brakes? Are the rear brakes otherwise just a regular air system? The brake system seems to have been serviced fairly recently, the front calipers have a new hose and very new looking dust boots on the pistons. Looks like a rear chamber was replaced and the air line near the rear end looks newish.

The owner said the truck had been sitting since last August when they started running their two newer Freightliner FL70 trucks full time and the Midliner went to standby. It started instantly, if he had already started it today it'd been a while before -- I checked the engine over before starting and it was cold. Smoked a bit on startup, smelled like too much fuel/old fuel/sticky injectors. Gauges seem to all work, 30 PSI oil pressure at cold idle. Air pressure built OK. There's an air leak at the low air warning switch. Low air warnings don't work unless they're disabled when the park brake is on (it's got a light for that, which does work). Didn't think to try and drop pressure with the park brake released.

Shift is a bit loose but not impossible to work. Better than the old 1970 MB I test drove a few years ago. Power steering may have a very slight seep but it looks like hardly anything. Power steering is adequate -- not hard to turn at full stop, and not super touchy. I only drove around the yard and a section of the little secondary road near the shop, but steering didn't feel sloppy. Brakes felt solid, I gave them a good hard application and locked the wheels up. Typical air brake lag which is why I'm wondering if the air-over-hydraulic is air servo control over the front discs only.

Box is dry (they just had a heavy snow), rear roll up door works but is a Whiting, side door needs a little help. Lift gate works but sounded low on fluid.

Shut it down, blew down the air tanks. Water in both, about a cup in the first and enough to make mist in the second. Steer tires are OK, tread is a little low. Rears have good tread but are starting to get hairline cracks around the inside edge. Near zero rust on the chassis/frame, box subframe has surface rust (Superior body, way better condition than my last box truck's subframe, which was OK). Explained the situation and the seller agreed to come down to $5000. Still has a few days on its current inspection (expires 3/18).

So, what's everyone think? Run away from the air-over-hydraulic system? Truck seems otherwise solid for a 1990 model. I like how it drives, feels like twice the truck my little Isuzu NPR-HD was.

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That catalog is a 1992 version. Euclid has discontinued a LOT of parts since then. Those "T" cams have always been very expensive. I always used the Mack dealer for parts and never had problems but even they were starting to see problems in the mid 2000's with the Mid-Liners. 

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Yeah, I figured some of the stuff had been discontinued, but it gives confirmation that the brakes on the Midliner I looked at *should* be full air S-cam, and not air-over-hydraulic drum or T-cam.

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2 minutes ago, glitchwrks said:

Yeah, I figured some of the stuff had been discontinued, but it gives confirmation that the brakes on the Midliner I looked at *should* be full air S-cam, and not air-over-hydraulic drum or T-cam.

I only had CS-300P chassis myself but I've seen CS-250P chassis with the troublesome brakes that were air over hydraulic and you really wanted to stay away from them. They always had the 175hp engines also with the one long valve cover as a dead recognition feature. The rear brakes were sorta like the Lucas-Girling types used by Ford in the 80's and 90's. Great till they started giving problems, then hold onto your wallet. Myself, never have seen full air brakes on a CS-250 but that is just me and the chassis were not all that popular in the midwest in comparison to out east. Does this truck use hub reduction axles, or is it conventional drive? All my trucks had 12k steer, and 21k rears with hub reduction, double framed and were very trouble free. All were conventional full air brakes. I rotated them through at 250k before they started becoming troublesome but really good trucks given the use/abuse they received.

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Posted (edited)

We had full air CS250s in the 90s. 

I believe full air for 250s became standard in the early 90s.

Planetary hubs on rears were standard on 300 series.

 

 

 

 

Edited by bbigrig

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Newest Mid-Liner I had was a 1992 CS-300P and it too was a very good truck. All had BDSL-181 transmissions which gave no problems. When looking for the first truck I was warned about parts and the brake system on the 250 series. Only thing I did to modify the brakes on the 300 series was to install larger quick release valves to set the brakes. The trucks were long and exhausting the air through that valve between the seats only is a waiting game for the brakes to set. 

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Posted (edited)

Think I'm going to go ahead and purchase the one I looked at Monday. Seller seems honest, truck starts, runs, and drives nice. Price is better than I can do for a non-beat Isuzu NPR or Mitsubishi Fuso, and most of those are going to be *gag* automatic transmission. I'm pretty sure I can adapt the air pack from a military trailer if I ever end up with a dead air over hydraulic servo, or just put a full air front axle under it -- where it's already set up with full air on the rear axle, it shouldn't be a huge deal.

Probably try and move it by the end of the week as it's still got a valid inspection!

Edited by glitchwrks

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Picked up the truck today, drove home about 100 miles, no issues. Got the hang of the transmission, which is a Spicer 5-speed. First acts unsynchronized, not sure if that's intentional or not :)

Definitely not the fastest thing on the road, but totally adequate for what I'll be doing with it. I poked my way home on US-220 and US-11, avoiding I-81 until it merges with US-11 north of Buchanan. Cruises at 60 MPH at 2100 RPM, which seems to be where it's happiest -- very quiet, didn't have to downshift going up the grade toward the Buena Vista exit. Could use an alignment I'm thinking.

Owner confirmed that brakes were gone through in 2016, had receipts to show it. Looks like it has automatic slack adjusters on the rear brakes, previous owner thought it did and I couldn't see anywhere to adjust them. I gave it a few hard stops before heading home.

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Looks pretty good!

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On 3/27/2018 at 8:39 PM, glitchwrks said:

Think I'm going to go ahead and purchase the one I looked at Monday. Seller seems honest, truck starts, runs, and drives nice. Price is better than I can do for a non-beat Isuzu NPR or Mitsubishi Fuso, and most of those are going to be *gag* automatic transmission. I'm pretty sure I can adapt the air pack from a military trailer if I ever end up with a dead air over hydraulic servo, or just put a full air front axle under it -- where it's already set up with full air on the rear axle, it shouldn't be a huge deal.

Probably try and move it by the end of the week as it's still got a valid inspection!

Totally agree with you..... I'm about to buy a cs200 too.... and I plan to change the front axle to full air.... just gonna need hoses  ... and bigger air tanks ....

Keep in touch and let me know how your truck runs......

I heard they are strong and fuel efficient

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This truck looks great...... very clean and nice ...... I thought u were talking the cs200 though

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Nope, MS200P! I like cabovers for the maneuverability and visibility. Apparently the CS cab shares the same cab part.

It's definitely not super fast on the highway, but it's fine, and judging by the drop in diesel fuel it's doing OK on fuel efficiency. Better power than the 1999 Isuzu NPR-HD I had. I'd have probably paid $1000 more for an equivalent truck with overdrive, keep an eye out for overdrive if you plan on doing much highway travel. With the 1:1 top gear on the 5-speed it seems to really like 60 MPH on the interstate, which I feel is fine.

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Yes I've heard they are quite fuel efficient.... how about the engine parts.... having any trouble finding any?..... how about the filters..... oil and fuel

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Can't stop looking at how clean it looks ..... I love it 

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Filters seem to be no problem, there are NAPA Gold (Wix) crosses, the ones that are on it are Hastings. I've heard engine parts can be hard to source, but that these engines are also pretty reliable. This one had been sitting since last August and aside from a fair bit of diesel smoke on startup, it started instantly and idled nicely, so I'm hoping there's nothing major to do on it. I did dump a bottle of Stanadyne lubricity booster in, since the pump governor acts sticky on startup (you can stab the throttle, RPMs jump up, but then it plunges below idle and takes a second to recover). Inline injection pump seems to be holding up to modern ULSD fuel.

I'm going to replace all of the belts and original-looking coolant hoses, I'm sure I can get the belts at NAPA, but we'll see how it goes with the formed hoses. I don't like using generic flex hoses if I can avoid it.

And yeah, aside from a few dents and dings, mostly on the box, the truck seems to be in really good shape!

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The truck is in amazing shape......

I checked the wix oil filter online......

It seems to fit the cs200.......

Do you think the same filters can work on both your truck and the cs200...

Someone told me....just change the oil and filters very regular and on time and that engine lasts forever 

 

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        This 1980 Mack "MS-200" is for sale down the road from you on Alt. 17 in Walterboro, SC. I drove a 1980 Mack "MS-200" freight truck in the early 1980s. 

        A basic, no frills truck but I liked it.

                                                           bulldogboy

DSCF0763.JPG

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Aw man, why did you have to post that truck?! :P What are they asking for it?

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glitchwrks:

I don't know. I was passing by on my way to Charleston, saw it, and had to take a picture. Three years ago I passed the same location and they had a Mack "CF" fire

truck for sale. It looks like an antique shop and they like to collect old Mack fire trucks. This photo was taken the end of March, 2018.

                         bulldogboy

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