I have a 615c scraper with a cushion axle that when engaged makes a hard bang and jolts upward and then rises to ride height. It seems to work fine once up but the jolt scares me away from using it for fear of tearing something up.its been like this since i bought it. When lowered it seems to settle cab side first then other side follows, like its not lowering level. I've been told that the accumulator could use a charge but haven't done much research on this issue and don't completely understand this system. Has anyone heard of anything like this or know anything about it?
Don't know a whole lot about it, but the accumulator would be the first thing I would have checked, that's what puts the "cushion" in the hitch. Wiser men may have better advice......
If you haven't checked the pre-charge in the accumulator that would certainly be the first place I would start.
Thanks guys. Kinda the direction I thought I should start.
After checking the charge in the accumulator (and if it's OK) the next place I would be looking is the RH side suspension cylinder because you say the cab side goes down first followed by the other side. Maybe there is something amiss inside that RH cylinder that is causing it to hang up. When the suspension "goes up with a hard bang" does the cab side lift first followed by the RH side..? Does either side jump up at all..? You may need someone under the machine watching it to determine what's happening, or even to get a better idea where the bang is coming from. Are all the suspension cylinder pins and front axle pivot pins lathered in grease..?
Yep. I would check all your linkages after checking the charge on the accumulator. We had several older machines that had the same bang. No other faults just a bang. Ours noise was right at the valve when engaged.
Thanks guys. Sorry for late reply. Dozers been keeping me busy and haven't been on H.E.F. In awhile. ,gonna check accumulator first and go from there. Linkages are well greased and seem to be free. In answer to your question nige the right side jumps up first but cab side follows close behind..... Let me add this detail... The right tire is the same size (26.5x25) as left but is 3 in shorter in diameter. I had to replace right tire when I bought machine. I wanted to match left Yokohama tire that's like brand new but after weeks of searching a rep told me it was unavailable...... And it was 6k!!!! so was forced buy what I could get. So now I have to buy a second tire of same brand and sell the Yokohama... Just so I know sizes match correctly.... Otherwise can't be good for differential.... Point is could the tire difference of 3 in affect cushion axle because machine sits slightly to the right?
615c I done over 10000 hrs on one of them and they do bang when the accum is low and they still bang when charged properly but not as bad
Regarding your tyre question. I wouldn't have thought it would affect the axle/suspension linkage. Have you checked the accumulator precharge yet..?
I wouldn't think tire difference would affect it either but I changing tire because I'm more concerned about causing a differential problem....has anybody ever had a same size tire with big actual size difference ? Scraper has been sitting and dozers going like crazy so haven't had a spare minute to check accumulator..... I'll let u know what I find out hopefully soon
FWIW the maximum recommended difference in size between tyres on the same axle is 3%. The easiest way to measure it is put a mark on the tyre and on the ground then move the machine to rotate the tyre one revolution. Measure the distance moved, repeat for the other side.
Thanks nige. Good info. I'll measure it out but sure it's outside of a 3% range but I'm curious by how much now . I'm gonna change tire regardless just for size match