dongfeng tractor with y385t wont start help

[reelnative]

do you guys think its smart to put all new bolts in or am i going overboard and should just replace the one i broke

 

[Bob Rooks]

do you guys think its smart to put all new bolts in or am i going overboard and should just replace the one i broke

At this point I'd go for all six. :thumbsup: They are cheap insureance against the previous owner (deliberately misspelled).

 

[reelnative]

yea bob Im deff gonna do all of them, hey what do you think about that dig torque adapter thingy I got yesterday, have you ever used one of them ?, I checked all my wreches today with it and it kinda made me feel good knowing that 2 of my 3 wrenches were good, i think a must of left my 1/2in that I was using with it up in the 60 to 70 torque setting for 6 or 8 months and thats what made it read so low, im gonna run it up and down 10 times or so and then ck it again, ive herd sometimes you can get them back into spec by doing that

 

[Rich Waugh]

That broken bolt has the appearance of a torque-to-yield fastener, what with the shank being smaller than the threaded portion. May or may not actually be a TTY bolt, but if so, they're designed to be replaced when removed, not reused.

In any case, having broken one, I'd certainly replace all of them. They cost what - a couple bucks apiece? Small price to pay for peace of mind, eh?

 

[reelnative]

i think they are reusable bolts but at 6.00 each I ordered a set of 6, the shaft of the bolt has a hump on it in the center to align it in the rod so theres no side play,as for there torque, well im about ready to pull my hair out, ive called all over the USA speaking to many diff guys that rebuild these tractors and everything I can find on the net and there are people using torque ranges from 40 ft lbs up to 95 ft lbs, the y85 book calls for a range from 81 to 95 ft lbs, does anyone know of a site that could tell me what the torque rang of a 16mm 1.5 bolt is im not sure on the thread pitch but it does look semi fine looks like a 1/4 20 , im thinking im going to torque them to the lower side of what the book says and do them around 81 to 82 ft lbs, i did speek to george at keno tractors and he has rebuilt many of these y385 engs and he told me he torques them dry to 80 ft lbs and has not had one come back yet

 

[Affordable]

The Y85 book does call for 81- 95 ft lbs, but the bolt is a 10mm bolt ( 16mm Hex head) and if you look at a bolt torque chart for a Grade 8 10mm bolt the spec is around 47 ft lbs. I have sent a e-mail off to my contact at Yangdong engine factory to see if they can give me a confirmation,

Tommy
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[reelnative]

yea but does the thread make a differance, and when i took them out they had way more then 47 ft lbs put on them, it was more like 100 ft lbs or more

 

[reelnative]

somthing is way off here i just found a metric chart and it is saying that a grade 8.8 10mm bolt max dry torque is 33 ft lbs and a grade 10.9 is 47 ft lbs should we be looking at the thread with or the bolt head size because if its the bolt head size then a 16mm bolt with a low grade has a torque range of 60 to 94 ft lbs and a grade 8.8 has a max torque of 146 ft lbs, im thinking that a bolt torqued to 47 ft lbs isnt gonna stay were it should being slinged around 2000 time a min and getting streached and pulled in diff directions the whole time for hours at a time

 

[Rich Waugh]

Nope, you go by the diameter of threaded portion, not the head size. The chart figures are based on a thread engagement of 1.0 times the bolt diameter, (basically, the thickness of a nut) if I'm not mistaken, and in use where there is more thread engagement that that the torque may be higher. Also, those bolts may be grade 12.9, which would have a torque value of 62 ft/lb versus 53 ft/lb for grade 10.9 or 37 for grade 8.8, according to my chart. Another chart have shows values of 70, 60 and 40, respectively, so even the charts don't necessarily agree. Values can also change if the material the bolt is threaded into is different than steel equivalent to the bolt itself. Lots of variables, in other words.

I'd use a torque value from the chart for the grade of bolt you have, and disregard the book. Use a drop of blue Loctite on each thread and you won't have to worry about them loosening from vibration.

 

[reelnative]

hahah ok so how do you tell what it is it has 3 lines on the top of the bolt and a cap letter i in the center, when i took the old ones out they were a lot tighter then 80 ft lbs prob in the 100 ft lb range I know it is allways harder to take them out then the ft lbs to put them in but not 40 or 50 ft lbs maby they are tty bolts