I'm finishing up my front disk brake conversion on the Poncho - non booster (for now). Everything is still under the floor and I've added the proportional valve and residual valve. I've got the system bled properly and getting ready for its first run. What is the proper/safest way to road test a new setup like this? Somehow going out and slamming on the brakes doesn't seem like the best of practices. Cheers Thanks
Find a road you can safely stop on without causing any problems to burnish/break in the pads. Run 35- 40 mph and make 10-20 stops about a mile apart for cooling. Deceleration should be technically +/-12 fpsps, but is close to a quick stop light change. Check for excessive heat or smoke and occasionally get out of the car and feel the wheels. You won't hurt the used rears and will probably improve their effectiveness. If all is well, you can now perform some higher decel stops to check axle bias and overall performance. You want the fronts to always slide before the rears.
For an untested system / Stop from less than 1 mph Work your way up to a stop from 3mph then 5 then 10mph. Then 20 mph then 30 mph then if you feel confident with no locking, no pulling or anything else stupid or unnerving weird noises, dragging, whatever then go on a road test and follow V8 bob's post.
Did you install an adjustable proportioning valve? It should go between the master and the rear brakes. Really the only way to adjust anything on the brakes assuming that the rear drums are adjusted with a slight drag is to drive about 35 mph and do a hard panic stop. If the rear tires skid then close the valve clockwise a full turn and test again. Keep closing the valve to the rear until it stops on a dime with no skidding. It sounds primitive but every car is different... vehicle weight, suspension , shocks and tire size all affect the adjustment that is why there is no possible pre set brake combo that will work without fine tuning the pressure. I recently installed a Speedway Motors disc kit and proportioning valve on my '59 Chevy Apache and on the first test it locked up the rears and that was with the valve set in the middle . It took three tries at closing the valve until the skidding stopped . Now it will stop on a dime in any panic situation . The disc conversion was the best improvement And more than I expected but it was the PRESSURE TUNING that made the brakes work like they should!! Sent from my iPhone using The H.A.M.B. mobile app
I've broke in a lot of brakes and tested them pretty much the same way V8Bob suggested. Safe road to hit the brakes with not traffic around and several gentle stops spaced out a bit between them.
This is how I would start! taking it up to 30mph and doing a brisk stop works great if everything is good, not so good if something is wrong. (Like a frozen/jammed caliper, or a split line)
Thanks for the help. The rears only have about 3000 miles on them since I did a Blazer rear axle swap several years ago - needed very little adjustment to get a slight drag on them. If the weather holds out this week I hope I can get out and give them a try. Thanks again !!!
I also use V8 Bob's method except I try to not let the wheels actually stop rolling with brakes applied, just down to a very slow roll. Have read that if the brake pads aren't yet fully seated and you stop with hot brakes with the pads still pressed against the rotors, there's a possibility of material being transferred from pad to rotor. Then you get a pulsing effect like a warped rotor. Have used this method many times with success on OT, heavy, high performance cars that put a lot more load on brakes than the average hot rod.
Excellent suggestions here, the only thing I would add is.....before you even leave your shop....slam the brakes really hard as if you were in a panic situation. You're better off to blow a line or etc in your garage than out in a real situation. If your braking system can't handle a hard panic stop, then it's not safe to be driving on the road.
The Jalopy Journal
