Troubleshooting brakes
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| + | When trouble shooting brakes do the easy things first. To develop good customer satisfaction for your shop and not waste your time, get to the true root cause first and fast. | ||
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| + | Check the fluid level of the master cylinder and look for obvious leaks around master first. Fill the master and replace the top, then pump up the pedal with the engine off. If the pedal becomes firm and then slowly leaks down; the leak is internal in the master itself, or it is external and small. If the pedal leaks down fast, you have an open line. This is a burst flex hose, missing bleeder, broken line, failed (open) wheel cylinder, leaking caliper or other mechanical damage. If the pedal will not pump up at all, there is a large leak or the master internal piston seals have split or failed. You will need to rule out a large external leak. If the pedal pumps up, gets spongy and then stays firm and doesn’t leak down you have air in the line and not a leak. You will have to bleed the brakes and then diagnose how the air got in. | ||
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| + | Start at the furthest rear tire and check the back of rear drum for signs of leaks, fluid slinging on the tire or discolored patches where the leaked fluid has collected dirt. Trace brake line to other tire until you find indications of a leak. Follow the path of brake line to the flex hose and then along frame until you see signs of a leak. Check the proportioning valve near front of the frame, check left front tire, caliper and flex hose for signs of leak. | ||
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| + | Follow brake line back to firewall and master, then follow line across to passenger side (right front) tire and look for leaks. After all this and no signs of leaks are found look at this caliper. Is everything within normal limits or is the caliper all the way out, rotor excessively worn or cut? Check the other rotor, is the condition and wear patters similar to the other side? | ||
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| + | Assuming the fluid level in the master is still good, take a pair of pinch–off pliers and pinch off the Flex hose that joins the rear breaks to the frame. Pump up the brakes. Is the pedal now firm and not leaking down? If yes, then the problem is in the rear. Remove the wheels and inspect the rear drums, shoes and wheel cylinders, or inspect the Rear Rotors, pads and calipers. Repair, remove and replace the items needed to restore the system to OEM specs and serviceability. If pinching off this hose made no change, then leave the hose pinched off and then continue to diagnose the system. Follow the lines along the frame back up to the master and try to notice any signs of obvious leakage. | ||
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| + | Find the flex hose on the right side caliper and use another set of pinch off pliers to pinch off the flex hose between the line and the caliper. Check the level of the fluid and pump up the brakes. Is the pedal now firm and not leaking down? If yes, then the problem is in this caliper. If the wheel is still on, remove the wheel and inspect this caliper and surrounding structure. Repair, remove and replace the items needed to restore the system to OEM specs and serviceability. If one caliper is bad expect to do both as the brakes should always be done as a set. | ||
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| + | Find the flex hose on the left side caliper and use another set of pinch off pliers to pinch off the flex hose between the line and the caliper. Pump up the brakes. Is the pedal now firm and not leaking down? If yes, then the problem is in this caliper. If the wheel is still on, remove the wheel and inspect this caliper and surrounding structure. Repair, remove and replace the items needed to restore the system to OEM specs and serviceability | ||
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| + | If after all this and the pedal still will not pump up or hold a pedal, re-inspect all the lines from the master to the flex hoses, use a flash light if needed to inspect the lines running along the frame and again look for leaks and signs of leakage. | ||
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| + | To Positively rule out a bad master cylinder, unhook both brake lines and cap them off with brass caps of the proper thread. Plug the outlets of the master cylinder with the correct threaded brass or steel plugs and top off the cylinder to the proper level. If the pedal pumps up and holds a pedal the master is ok. If the pedal pumps up, is spongy but then holds a pedal and doesn’t leak down, then it has air in the outlets and needs bled. Bleed the master cylinder and reconnect the lines. If the pedal will not pump up or will not hold a pedal at all, the entire master is not good and needs replaced. | ||
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| + | You should now know where the leak is and how to correctly price out the repair for your customer. | ||
[[Category:Brakes]] | [[Category:Brakes]] | ||
[[Category:Undeveloped articles]] | [[Category:Undeveloped articles]] | ||
[[Category:Troubleshooting]] | [[Category:Troubleshooting]] | ||
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