jackb61sx Posted February 3, 2013 Share Posted February 3, 2013 Have an 89 Superliner RW753, we where working on the front this weekend and had pulled the drum to replace studs fro front wheel. So as we where inspecting things we thought the brakes looked to good on the front, so I climbed in hit brake and low and behold they did not move. Went under the truck and pulled lines off valve under bumper put air to line to the cam and the shoes moved. So now we need to reace lines back and find where the issue starts. Any help appreciated in sending us in the right direction Quote Link to comment Share on other sites More sharing options...
HK Trucking Posted February 4, 2013 Share Posted February 4, 2013 Could be that proportioning valve under the front bumper is defective & not letting any air through. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment Share on other sites More sharing options...
jackb61sx Posted February 4, 2013 Author Share Posted February 4, 2013 Checked that and getting no air to the valve it appears. Quote Link to comment Share on other sites More sharing options...
2stacksuperdog Posted February 4, 2013 Share Posted February 4, 2013 I would say just trace it back Quote Matt Link to comment Share on other sites More sharing options...
jackb61sx Posted February 4, 2013 Author Share Posted February 4, 2013 figured that, heading for the treadal valve Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted February 4, 2013 Share Posted February 4, 2013 Make sure all of the tanks have air in them. Quote glenn akers Link to comment Share on other sites More sharing options...
jackb61sx Posted February 4, 2013 Author Share Posted February 4, 2013 will check them,,,we do have the air drier by was not working right, froze up last week in the real cold weather. I am going to replace with a new one and not bother to rebuild. Quote Link to comment Share on other sites More sharing options...
RowdyRebel Posted February 4, 2013 Share Posted February 4, 2013 Whuddaya need brakes fer? Alls they do is slow ya down! Quote When approaching a 4-way stop, the vehicle with the biggest tires has the right of way! Link to comment Share on other sites More sharing options...
thomastractorsvc Posted February 12, 2013 Share Posted February 12, 2013 what did you find out? they were pluged off? Quote Robert"I reject your reality and substitute my own." Link to comment Share on other sites More sharing options...
jackb61sx Posted February 13, 2013 Author Share Posted February 13, 2013 Have not gotten to work on yet, The snow last weekend changed my plans spent last 4 days in a backhoe. Plan to work on this Sat, sent the truck out to have it all steam cleaned underneath so we could see what we where doing. Will let you know what we find and thanks for asking. Quote Link to comment Share on other sites More sharing options...
jackb61sx Posted February 16, 2013 Author Share Posted February 16, 2013 what did you find out? they were pluged off?Well finaly got to work on truck today in the shop, no 30" of snow to move. I powerwashed all underneath the truck to remove all the crap and we where able to follow the line up to the new tredle valve that was added prior to my purchase. Removed the line to the front, released maxis and applied brakes and had air going to front valve, so we remoed the line at the bumper and attached again at tredle and applied brake and sure enough had air through hose to that valve, connected hose back up there and front brakes now work. We figure that something either came out of tredle valve or had something in the line. But thanks for advise and asking.....Jack Quote Link to comment Share on other sites More sharing options...
cl733 Posted February 25, 2013 Share Posted February 25, 2013 on the rd models we used to have they had a valve that had to have 35 psi applied to it before it even started applying air to the front brakes Quote Link to comment Share on other sites More sharing options...
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