Got a machine here and my question is this. When you put pressure to the steering clutch piston to release the steering clutches, is that piston completely sealed? I currently have the brake actuator cover off and if I start the machine and pull the steering clutch lever, I can visually see a fair amount of oil leaking from around the steering clutch piston area. As soon as I let off it quits. Now obviously there is a fair amount of oil flowing already from the brake cooling line dumping oil on/into the brake bands, but this other leak is very noticeable over and above this. My second question is, does anybody know if the steering control valve applies the full 400psi to apply the brakes when doing a hard turn? I have 400psi to the brake housing (at the little 1/8” pipe plug port on the brake actuator housing) when I press the brake pedal. It also will modulate depending how hard I push the pedal. But if I pull the steering lever all the way as if to do a hard turn, im only seeing 190psi. Both left and right is the same. The machine is semi struggling to do a hard turn so this is why Im investigating. The brake bands/drums seem glazed. At a very low idle in 1st gear you have to STAND on the brake pedal to make the machine stop with just one brake pedal. Anything much above a very low idle and it will not stop unless you use both pedals. It does seem like the steering clutches are releasing despite that big oil leak, when I block the track and put it in gear, I can see the clutch release and start spinning when I pull both levers.
Never did that test. But I would take a guess they will leak a smich since if memory serves they are nylon square rings as seals and not lip seals like many clutches have in automobile automatic transmissions that will seal close to 100%, was it warm when doing this test? Old D8 steering is pretty sluggish till they warm up. Hope others have some input on this as well.
You should check all the linkages and the rollers on the ends of the steering valve spools. I've never bothered to look in the steering and brake compartments to check for leakage. Usually if they didn't hold full pressure we just pulled them. There was always something wrong. If the linkage is good and both sides are doing the same thing, you might have a bearing problem on the cross shaft. That is big problems and big dollars to fix. Most people in this day and age just junk the machine at that point.
Steering clutch pressure with clutches released at low idle require a minimum of 275 psi to function properly. Brakes at high idle should make 390 +/- 25psi
I think you will find they will leak lots I know the AC's that i worked on at the dealership would spray lots of oil out even with new seals.
I thought I changed nylon to teflon? Nylon would likely melt.
Yeah they probably would deem it scrap at that point. Then this company I work for would buy it cheap and rave about the smoking deal they got.