Damicoexcavating Posted December 14, 2016 Share Posted December 14, 2016 My 1985 R688ST dump has broken the drivers side steering knuckle/spindle where the steering arm mount so I'm looking for either a front axle assembly Mack number faw537c (12,000 pound axle) or a knuckle part number 4qh312p2-preferably closer to Illinois if it's a entire axle.thanks Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/ Share on other sites More sharing options...
kscarbel2 Posted December 14, 2016 Share Posted December 14, 2016 Did you confirm 4QH312P2 is the correct part number based on your truck's model and serial number, and the 1QH front axle arrangement? When you contacted Watt's Mack (provider of the BMT website) at 1-888-304-6225 for a 4QH312P2 knuckle, what did they say? Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-354992 Share on other sites More sharing options...
Damicoexcavating Posted December 14, 2016 Author Share Posted December 14, 2016 Knuckle is still available buts it's pricey trying to find a cheaper alternative going into the off season Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-354997 Share on other sites More sharing options...
kscarbel2 Posted December 14, 2016 Share Posted December 14, 2016 41 minutes ago, Damicoexcavating said: Knuckle is still available buts it's pricey trying to find a cheaper alternative going into the off season The larger issue here is, you're using a tractor with a 12,000lb front axle as a dump truck. The frame and axles are not designed for such loads. That's why your steering knuckle failed. Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-355003 Share on other sites More sharing options...
Damicoexcavating Posted December 14, 2016 Author Share Posted December 14, 2016 Unless I'm mistaken or the front axle has been swapped out it's always been set up as a dump truck-will a heavier rated axle bolt bolt in as a replacement? Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-355039 Share on other sites More sharing options...
kscarbel2 Posted December 14, 2016 Share Posted December 14, 2016 You have an R688ST. "T" stands for tractor. Sales Engineering would never allow dump body fitment onto a regular R-model. The frame and front axle aren't up to the task. Even if you go to a heavier axle, then the tractor frame is the weak link. If you could upgrade to a 14,300 lb FAW538 front axle and springs, sure that would help. But it would be challenging to find one nowadays. An RD688S is a 6x4 dump chassis. "D" stands for dump. The RD has a deeper and thicker frame rail. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-355049 Share on other sites More sharing options...
ranchhopper Posted December 14, 2016 Share Posted December 14, 2016 Damn I took two front axles to the scrap yard this summer got tired of them taking up space one 12000 and one 20000 pound is your frame rail a double or single? Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-355070 Share on other sites More sharing options...
MACKTRUCKS4 Posted December 15, 2016 Share Posted December 15, 2016 Would a 12,000 lb axle have 6 spoke hubs? Quote Live every day like it's your last, because one of these days, it will be. Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-355100 Share on other sites More sharing options...
Damicoexcavating Posted December 15, 2016 Author Share Posted December 15, 2016 My truck is a single frame rail and going off my truck it's 6 spoke- I never looked on the axle for a part number I'm going off what Mack told my it came with so it could have been 5 spoke Quote Link to comment https://www.bigmacktrucks.com/topic/48025-front-axleknuckle/#findComment-355121 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.