Whiskymack Posted July 22, 2022 Share Posted July 22, 2022 I'm planning to build a scale model of the above based on the one that appears in Beverly Hills Cop 2. I'm using an AMT Kenworth Challenge mixer kit but building my own RL600 frame It has a front mounted hydraulic pump/tank and oil cooler but there is no mechanical drive to the pump included in the kit. The pump sits behind the front bumper extension not connected to anything! I have been told that there should be a drive shaft coming from the back of it which passes either under or through the radiator and connects with the large flywheel pulley on the front of the crankshaft. I have a couple of internet pics of a similar RL685 mixer but I just cannot see what's what. Can anyone explain how a front mounted hydraulic pump would be driven on an RS/RL model? Any pictures would be great. Many Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/ Share on other sites More sharing options...
mowerman Posted July 22, 2022 Share Posted July 22, 2022 Sorry I can’t help but I do remember transit mixed in Southern California had tons of those they were real nice looking rigs they were red with white barrels. I don’t know what happened to the company I left the area and 94 and a returned 5 years ago and they were gone.. bob Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-503864 Share on other sites More sharing options...
Freightrain Posted July 22, 2022 Share Posted July 22, 2022 Interesting project. I'm curious now if those were direct drive, full time pumps(likely). Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-503881 Share on other sites More sharing options...
RoadwayR Posted July 22, 2022 Share Posted July 22, 2022 That mixer in the movie was a old Livingston-Graham unit, they had a lot of R model mixers. Bonanza and Conrock had them too. You are correct about the pump drive, there should be a shaft coming off the engine crank pully passing under the radiator driving the pump. The front frame crossmember had a U-shaped hole for the shaft to go through. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-503887 Share on other sites More sharing options...
mrsmackpaul Posted July 22, 2022 Share Posted July 22, 2022 The shaft would be under the radiator as the crank is bellow the radiator And it's told to "blue tooth" it across, blue tooth wasn't even invented then 🤔 Paul Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-503892 Share on other sites More sharing options...
Whiskymack Posted July 24, 2022 Author Share Posted July 24, 2022 Thank you for all the suggestions. I think I have found the answer. It looks like there is a square opening in the bottom of the radiator core for the shaft to pass through. The Radiators on RS/RL models are tall and drop down below the level of the crankshaft so I guess the opening was the only way it would work. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-504051 Share on other sites More sharing options...
JoeH Posted July 25, 2022 Share Posted July 25, 2022 I have a DM686sx that was a barrel truck. 1980. Has a monster bumper, I'll try and get a picture of the radiator/pump bracket. Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-504155 Share on other sites More sharing options...
JoeH Posted July 25, 2022 Share Posted July 25, 2022 Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-504159 Share on other sites More sharing options...
JoeH Posted July 25, 2022 Share Posted July 25, 2022 I have a 2003 MR688S also that had a pump on the front. It has the tall radiator like you mentioned with a hole through the middle. let me know if you want pictures, but it is a different model altogether. Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-504160 Share on other sites More sharing options...
JoeH Posted July 25, 2022 Share Posted July 25, 2022 The pump is live, always on. On trash trucks, the pump has a protection circuit. If the hydraulic system loses oil, a butterfly valve closes and oil is circulated through a metal pipe from the pressure side of the pump to the suction side. This way you can limp the truck along without destroying a $3,000 (guessing) pump. Quote Link to comment https://www.bigmacktrucks.com/topic/70154-rl600-concrete-mixer-question/#findComment-504161 Share on other sites More sharing options...
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