M8950 DT No Brakes!!!

Tim Steele

New member

Equipment
Kubota M8950DT
Mar 18, 2017
6
0
0
Front Royal, VA
No brakes!!!
2 days ago I was rolling up to the hay ring on a slight down hill with a bale on the spear going slow thank God , hit the brakes and both pedals bottomed out. Luckily I had presence of mind enough to cut the wheel and head the tractor back up hill to level ground. I got the twine off and the bale in the ring, then headed back to my shop. I suspected a line rupture or some other breach but found the reservoir full when I pulled the RH side cover off. Further investigation showed no leaks anywhere. The only damage I saw was torn boots on both brake cylinders but again no fluid loss. I had the pedals locked together and once I separated them I found that vigorous pumping of the left brake pedal yielded enough pressure to get a pedal back and enough stopping power for one application that would stop the tractor with that side. The RH pedal will not build any pressure. So I called Kubota and bought 2 new brake cylinders to the tune of $404.00 shipped. I had to beat the pins out of the clevises but other than that the disassembly was uneventful. Kubota shop manager said he never saw both fail at once. He also told me initially he thought it might be internal failure which runs into big money to fix but no fluid loss tenatively rules that out. So long story short on my break from work this week I will complete the reassembly and attempt to bleed the brakes and hopefully get some brakes back on the tractor... I have the new cylinders about 1/2 installed. Any help or advice is most welcome. Thanks in advance.
 

Tim Steele

New member

Equipment
Kubota M8950DT
Mar 18, 2017
6
0
0
Front Royal, VA
No we didnt try and bleed them before we changed the cylinders but we did after. The shop manager at my local Kubota dealer is puzzled as well because of the lack of fluid loss. They went from working perfectly to not at all and they still dont work. I followed his bleeding instructions of hold one pedal 1/2 way down (something to do with the positioning of a valve) and pump the other and the left brake will build pressure but will only sustain it for one application. The right brake wont build pressure at all. I bled them with a hose hooked to the bleeders in a mason jar with brake fluid in it and thought I had it bled but only had pressure for one application. Then I hooked up my mityvac brake bleeder and I get air bubbles. Bled them over and over but still the same result. I am thinking the frictions on the brake packs are worn clear out or something else internal has failed but why doesn't the fluid go somewhere? I probably wasted $400. I am a pretty decent mechanic but I am stumped. I plan to talk to the service manager again tomorrow and get an estimate for a brake job. Looking at all the stuff thay has to come off to get to the brake packs ( they look like a clutch pack setup on a motorcycle with frictions and steels in the picture he showed me) I am sure the labor costs will be quite large. Not to mention the parts if those two little cylinders were $400 so no telling what the parts cost will be. Any advice anyone has will be much appreciated.
 
Last edited:

Tim Steele

New member

Equipment
Kubota M8950DT
Mar 18, 2017
6
0
0
Front Royal, VA
Yes just like he told me to. We hooked the supply lines up and filled the reservoir and pumped each one without the pedal hooked up and the brake line disconnected until we got our thumb pushed off the hole and a steady stream of fluid, then hooked up the brake lines. It has to be either air or some internal wear or failure?
 

Tim Steele

New member

Equipment
Kubota M8950DT
Mar 18, 2017
6
0
0
Front Royal, VA
I spoke with my friend the Service Manager and was quoted $1200 parts and labor if I can haul the tractor there for a complete brake job with all new frictions, steels and internal seals and orings way better than I expected.