1981 Mack Fire Pumper ... Brakes

tc35dforme · Feb 26, 2003

Okay guys,

Once again I turn to the collection of knowledge known as TBN.

When I'm not attempting to work or doing the TBN thing, I serve as a Lieut. on our local fire department. We are currently considering purchasing a used fire pumper to serve as our reserve truck.

The unit is a 1981 Mack EM6-285. One of our committee members has expressed concern with it possibly having 'Kelsey-Hayes' brakes.

I freely admit to being a big truck idiot...

Is there any concern with Kelsey Hayes brakes ? Have any of you guys had any experience with them ? Thoughts or Comments.

Thanks

RobS · Feb 26, 2003

I can't imagine that being a problem. No doubt it has air brakes. Parts for medium and heavy trucks are available for much longer than pass car/light truck. Kelsey Hayes was bought a couple of times since then, now I believe it is Hayes/Lemerz. I wouldn't let this affect your purchase /forums/images/graemlins/smile.gif

Anonymous Poster · Feb 26, 2003

I'm thinking back when I owned my truck-tractors and it seems to me that 80 - 84 or so model year trucks with Kelsey-Hayes brake systems (not necessarily restricted to Mack) were very problematic. This was due to that overnight vote of congress that trucks had to have anti-lock brake systems. These systems were designed literally over night or so it seemed. Along 85 -86 or so the bugs were worked out. 99% of the problem was electronic sensors which triggered brakes when not needed or didn't trigger them at all. The last large car that I bought was an 89 Navistar and it was problem free by this time. Memory is off some, I admit, haven't been in a rig since January of 91.

tc35dforme · Feb 26, 2003

lamarbur,

I spoke to the mechanic who works on the truck and he said that the ABS system has been disconnected and/or bypassed somehow. I believe it was a factory callback thing ?? early on.

Thanks for the input.

BobinCols · Feb 26, 2003

I would say about all trucks from the late 70's and early 80's with antilock brakes have been disconnected and changed over to regular air brake valves which is ok and safe. Most trucks have Eaton or Rockwell (Meritor) "cam" foundation brakes at the wheels. This truck with Kelsey Hayes should be air over hydraulic disc brakes on the front and standard "cam" air brakes on the rear drive axle. It could also have full air disc brakes on the front (again Kelsey Hayes). The air over hydraulic is much more complicated and the parts are available but expensive. The calipres are difficult to work on. Disc brakes on trucks do not last as long and are alot more expensive than "cam" brakes and do not stop as well. None of the fire departments we work for have trucks with the KH brakes any more. They were ok until you had to work on them and repairs are costly. The KH brakes should be on the front only and most likely Rockwell on the rear (cam).

hosejockey2002 · Mar 5, 2003

The fire department I work for ran Macks of various vintages for many years. I'm not sure what brand of brakes they used but they all had full air with drums all around. As far as I know we never had any major problems. Some of our older Macks (pre-1974) had a "front brake limit switch" which was supposed to prevent front wheel lockup by limiting the amount of air sent to the front brakes. Those were eventually outlawed and I doubt the '81 Mack has one. The 285 Maxidyne is a strong, reliable and economical engine. Our department has three Macks for sale, an '80 and two '84's, let me know if you are interested.