609albert Posted September 27, 2008 Share Posted September 27, 2008 Have a 47mack pumper that has no brakes, where do I start to fix them Quote Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/ Share on other sites More sharing options...
other dog Posted September 27, 2008 Share Posted September 27, 2008 Have a 47mack pumper that has no brakes, where do I start to fix them are they air brakes, hydraulic, or Fred Flintstone type? Quote Producer of poorly photo-chopped pictures since 1999. Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22310 Share on other sites More sharing options...
609albert Posted September 27, 2008 Author Share Posted September 27, 2008 Have a 47mack pumper that has no brakes, where do I start to fix them . They are hydralic, the pedal goes to the floor no resistance , the truck had been setting for months, their is a ''booster" tank mounted under the frame also. Quote Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22311 Share on other sites More sharing options...
Maxville Truck Posted September 27, 2008 Share Posted September 27, 2008 Fill the resevoir first.... then with a helper attemp to blead the air out. start at the farthest wheel then work your way to the front. If your cant get anything to happen, you might as well start with a new master cylinder.Your will most likely need the following componets1. Brake Lines, both rubber and steel2. master cylinder3. new bleeder screws or just the entire wheel cylinders (depending on how much acetylene or propane your use.... )4. Booster cylinder..5. possibly brake shoes, springs, adjuster kits etc.Good Luck!! Quote Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22313 Share on other sites More sharing options...
other dog Posted September 27, 2008 Share Posted September 27, 2008 That's a good start- I'd fill the master cylinder up with fluid first, then check for obvious leaks, starting with the master cylinder, then the booster, then all the wheel cylinders. If all that checks out OK, check all the brake lines for leaks. If they're all good, and even if you have to rebuild or replace any of the above, you'll need to bleed the system to get any air out, and you should have a good pedal. You'll probably have to jack each wheel up and adjust the brakes with a brake spoon through the slots in the backing plates too in order to get a full pedal...(condensed version). If you're lucky, maybe all they need is bleeding,but something had to cause them go away in the first place. You need an assistant too, to help with this by pushing the pedal down while you look for leaks and especially during the bleeding process, unless you use a pressure bleeder. Hope this is a little help anyway-good luck with your project. Quote Producer of poorly photo-chopped pictures since 1999. Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22314 Share on other sites More sharing options...
Greg Rider Posted September 29, 2008 Share Posted September 29, 2008 Make sure that the brake shoes are adjusted good first or you will be moving the pedal a lot without any resistance to build pressure. Invest in penetrating fluid and start spraying every bleeder.Do that for about a week. Be mentally ready to break a bleeder off, that way it won't surprise you when it happens. Quote #1 on A-model registryIf I drink because of work, why can't I drink at work? Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22346 Share on other sites More sharing options...
609albert Posted October 2, 2008 Author Share Posted October 2, 2008 Fill the resevoir first.... then with a helper attemp to blead the air out. start at the farthest wheel then work your way to the front. If your cant get anything to happen, you might as well start with a new master cylinder.Your will most likely need the following componets1. Brake Lines, both rubber and steel2. master cylinder3. new bleeder screws or just the entire wheel cylinders (depending on how much acetylene or propane your use.... )4. Booster cylinder..5. possibly brake shoes, springs, adjuster kits etc.Good Luck!! thanks for the advice, the truck has a hydr -vac system with a reserve vaccum tank on the other frame rail, I traced the line back from the reserve tank to the engine and and found it disconned (a pipe line from a sort of regulator on the firewall ) the line from this regulator to the manifold is gone and their is a plug threaded into the manifold. I don't know why it has been disconnected. Quote Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22439 Share on other sites More sharing options...
HK Trucking Posted October 2, 2008 Share Posted October 2, 2008 thanks for the advice, the truck has a hydr -vac system with a reserve vaccum tank on the other frame rail, I traced the line back from the reserve tank to the engine and and found it disconned (a pipe line from a sort of regulator on the firewall ) the line from this regulator to the manifold is gone and their is a plug threaded into the manifold. I don't know why it has been disconnected. Probably because the Hydro vac is shot, and they wanted to eliminate the massive vacuum leak. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22443 Share on other sites More sharing options...
609albert Posted October 9, 2008 Author Share Posted October 9, 2008 Probably because the Hydro vac is shot, and they wanted to eliminate the massive vacuum leak.[/ can the hydro-vac unit be rebuilt? If it was installed by mack I'm sure it is needed to properly and safely stop the truck Quote Link to comment https://www.bigmacktrucks.com/topic/4248-brakes/#findComment-22575 Share on other sites More sharing options...
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