Kelvin - here ya go !
Start with the slider pins first. I suspect that most piston seal failures occur because of the pins. If the pins are rusted, replace them - $6.99 at AutoZone (p/n H15017). Clean where the slider pin goes into the caliper bracket real well. Use plenty of a good, semi-clear synthetic caliper grease.
Check the operation of the parking brake cables, by having someone else engage/release the parking brake. If they aren't smooth, remove the cable from the caliper to see if the caliper parking brake lever is binding, or one of the cables is binding. If you think the cable(s) is/are hanging-up, releasing the parking brake pedal slowly will show if it is binding once removed from the caliper.
Below is a basic trouble-shooting guide that I have posted before, for working-through and "bleeding-through" the brake lines to determine where the problem exists. Print it out, review it, and highlight the applicable portions for what you're trying to correct.
Print this out and keep it handy when you get ready to start.
This is not an approved or certified diagnosis guide on how I
would trouble-shoot or repair my SHO, but how I would
approach brake issues if it were my vehicle.
I would start by pulling the passenger-side rear caliper and checking the condition of the slider-pins. If they're frozen or rusted and I'm able to get the pins out, I would try cleaning off all the rust. I've found a sheet of Scotch-Brite does a pretty good job of cleaning-up light surface rust - if the pins are pitted, I'd replace them. If in doing this it became apparent the pins were too far gone, I'd also buy a replacement bracket for $16.46 at Advance Auto:
Regardless of whether the slider-pins were rusted or frozen, I would clean/replace the pins/caliper brackets and pick-up a high-quality synthetic caliper grease - last time I checked it was $9.24 to $11.99 for a large 8-oz. bottle at most auto parts stores. I personally would use either Permatex (Advanced Auto - $9.24 for 8 oz.) or VersaChem (O'Reilly - $11.99 8 oz.) synthetic greases. While AutoZone carries CRC synthetic grease for $9.99, it is a dull black-gray grease compared to the green Permatex and blue VersaChem greases, which are semi-transparent and allow me to see when rust begins to develop during later inspections.
I've found it takes little time to inspected and re-grease the pins during every brake service, even if the service is to simply check pad wear. It's cheaper insurance than an oil change....
Next, I'd pull the driver-side rear caliper and check the slider-pins. Either cleaning/removing the rust or replacing as per above. When the caliper and caliper bracket have to be replaced - while the bracket and caliper are available as a complete caliper kit, I would check to see if it's cheaper to buy them separately:
In pulling both calipers (one at a time), I'd look at the condition of the brake fluid that leaks out. Is it rust-colored, cloudy, dirty, contaminanted (particles suspended in the fluid), or clear. Make a note for later reference here.
If contamination is noted in either rear-brake system, next I would check the corresponding opposite front-brake system. That is if the right-rear had contaminated fluid, I would next check and bleed the left-front caliper. Why?
The ABS system in the Taurus is setup using two ABS circuits (a primary and secondary circuit). The master cylinder aft chamber feeds brake fluid to the ABS primary circuit, which controls the right-front and left-rear brakes. The forward chamber feeds the ABS secondary circuit, which controls the left-front and right-rear brakes. Thus discovery of contamination at any one caliper means that the contamination may be present at the opposite-corner brake as well, which is indirectly connected via the ABS circuit.
As I prepare to bleed the rear brakes, I would support the left-rear hub with a 9.5"-10" (241mm - 254mm) long block of wood between the ground and the lowest two wheel studs. I use a a 2"x6" block, but a 2"x4" block can be substituted. The 2"x6" block provides better support, as the wheel studs are approx. 2.5" center-to-center and a "finished" 2"x4" actually only measures 3.5" across. I have found that elevating the hub places the proportioner valve at approximately the same position as having a standard-height tire installed.
I'd next, make sure the master cylinder is full and continue to check the fluid level as I progressed. I'd get a helper to lightly press on the brake peddle to see if brake fluid is flowing through the flexible hose. If you get no flow, progressively (slowly) increase brake pressure until you do. The following are generalizations I start with when initially trying to assess a brake problem, after I have checked the caliper bracket and pins. If I were trying to spend as little as possible, this is where I would start next.
- If the fluid flows easily, the flexible line is probably not collapsed.
- If the fluid spirts-out like it's under pressure or not at all, the line might be collapsed.
If the fluid spirts-out like it's under pressure, break-lose the flexible rubber hose from the hard-metal line on the rear subframe rail and remove the flexible hose. I'd repeat the test to see if the hard-metal brake line is free-flowing, or appears restricted or blocked.
- If the fluid flows easily from both the flexible hose and hardline, the flexible line is probably not collapsed.
- If the fluid spirts-out like it's under pressure from the flexible hose (or not at all), but flows easily from the hardline, the flexible hose is likely collapsed.
- If the fluid spirts-out like it's under pressure from both the hardline and flexible hose, the problem is upstream in the brake system, possibly in the master cylinder, ABS pump, proportioner valve, or the lines themselves.
I'd then replace rear brackets/calipers/hoses as necessary. I'd pick-up a 32-oz. container of Prestone Dot 3 brake fluid at WallyWorld which is less than $4 a bottle, instead of wasting higher quality brake fluid until the brake problem is definitely corrected. Then I would re-bleed and flush the system with new Dot 3, or Dot 4 synthetic fluid.
WHEN YOU ARE DONE BLEEDING THE BRAKES,
LOOK AT THE FLUID YOU HAVE BLED/DRAINED FROM EACH LINE AND FITTING.
- Cloudy fluid indicates chemical contamination or that the brake fluid is old - in either case it should be changed.
- Physically contaminated brake fluid (particles suspended in the fluid) is easily diagnosed by holding the sample up to a bright light source. The system/lines should be drained, flushed, and blown-out or allowed to air-dry before refilling with new brake fluid.
- If it is rust-colored, internal corrosion is present and could be coming from anywhere between the master cylinder and caliper. In this latter case, after the affected components have been replaced, the entire system should be drained, flushed, and blown-out or allowed to air-dry before refilling with new brake fluid.
Anyone else notice who's now showing-up on the Parts America website . . . ?
