Onyx610 Posted June 17, 2021 Share Posted June 17, 2021 (edited) Hi, I didn’t take notice to the bearing orientation when the clutch was removed. First time doing a clutch on one of these and couldn’t find info on it. To save me time tomorrow and looking at another truck I was curious if someone could guide me in the right direction. Does the round side face down or the flat side? As usual all your help is greatly appreciated. Edited June 17, 2021 by Onyx610 1 Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/ Share on other sites More sharing options...
Onyx610 Posted June 17, 2021 Author Share Posted June 17, 2021 Also how are you guys measuring release bearing yoke gap with the release yoke upside down? The 1/8th measurement. Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475333 Share on other sites More sharing options...
Popular Post theakerstwo Posted June 17, 2021 Popular Post Share Posted June 17, 2021 The flat side down but you who have found out when installing trans cause the fingers on the release fork would not went over the brg.Also put the grease hose on the trans side of the clutch fork shaft and not on the flywheel side. 5 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475334 Share on other sites More sharing options...
Onyx610 Posted June 17, 2021 Author Share Posted June 17, 2021 Thanks a lot! I just wanted to ask before getting to far into it. Just got the flywheel back from machine shop. Trans is rebuilt and new clutch is ready to go in. We are doing away with the hose (Vogel system) as it wasn’t working properly and the hose was also cut. The new bearing has 3 grease fittings on it. I was also curious how to measure the gap between release fork wear pads and bearing. I have some “tools” for it but it seems to be very difficult with the Mack’s fork being “upside down”. Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475335 Share on other sites More sharing options...
Popular Post fjh Posted June 17, 2021 Popular Post Share Posted June 17, 2021 (edited) This is just one of many ways to set a clutch ! others may argue how ever it works for me! Your correct its almost impossible to see on a Mack so this is my work around! 11/2 free pedal is equal to the 1/8 gap your shooting for at the fork! First set the clutch brake to work right at or 3/4 before the pedal reaches the floor with the arm adjustment on the out side of the trans! Then set the bearing to trans clutch gap with winder on the clutch to get the 1/2 inch gap between the bearing and the clutch brake! (You can use a half inch drive socket extension as for guide for this ) you should end up with aprox 1/8 gap at the fork its not written in stone you can have two inch of free pedal but the clutch will engage lower on the pedal on the way up and the the fork gap will be a bit larger ! The half inch gap will determine where the clutch starts to Engage and the 1/8 at the fork the smaller the gap between the brake and the bearing the closer to the floor the clutch will engage the larger the fork spacing ! the key here is to not have continuous pull on the crank it will over time take out engine main bearing thrust washers! not a great thing! seen this happen a few months back very expensive! YOU NEED TO HAVE FREE PEDAL always! Just sayin! Edited June 17, 2021 by fjh 4 Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475350 Share on other sites More sharing options...
Onyx610 Posted June 17, 2021 Author Share Posted June 17, 2021 Awesome information, thanks again you guys. I have heard so many different ways of doing this. I am going to give your way a shot sounds good to me! I’ll let you know how I make out with it. 🤞🏻👍🏻 Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475353 Share on other sites More sharing options...
Popular Post fjh Posted June 17, 2021 Popular Post Share Posted June 17, 2021 1 hour ago, Onyx610 said: Awesome information, thanks again you guys. I have heard so many different ways of doing this. I am going to give your way a shot sounds good to me! I’ll let you know how I make out with it. 🤞🏻👍🏻 Note the closer to the floor you set the clutch brake the better off you will be specially if you got multiple drivers that don't know what a clutch brake is for ! I also heavily coat the clutch brake with grease for this very reason if the driver is unaware when and how to use the clutch brake they can Ruin it in short order! Hence SET IT AS CLOSE TO THE FLOOR as you can! Again my opinion just a rule of thumb! 3 Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475355 Share on other sites More sharing options...
Onyx610 Posted June 17, 2021 Author Share Posted June 17, 2021 Ok I will do that for sure. We have plenty of guys that like to push the pedal to the floor rolling down the road. Somehow the clutch brake tabs haven’t broken yet. Not sure how. I did grease both sides of the brake too. Quote Link to comment https://www.bigmacktrucks.com/topic/67043-rd688s-throw-out-bearing-orientation/#findComment-475365 Share on other sites More sharing options...
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