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Rear Brake Caliper rebuilding write up.
I know labor wise, installing a new caliper is easier. However, being short on cash made me go with the rebuilding route. Actually, you are not rebuilding, just resealing. The calipers were not leaking, but the dust shields were about non existant.
I took some pics as well. Tools needed: Power drill and polishing flap wheel to polish the poston, if needed. Air compressor w/blow gun (if you have them) Two flat head screwdrivers 19mm 1/2in socket and ratchet 17mm 1/2in socket or proper wheel lug wrench 14mm flare wrench 11mm flare wrench 9 mm flare wrench Large Channel lock pliers Brake parts or carb cleaner Shop rags or paper towels 3in wide x 9in x 1/8in thick piece of steel, or something else you can find. I used an old 9in edger blade. Some sort of air block to use on the master cylinder. I used plastic wrap to act as a seal between the M/C cover and fill neck. That way you do not lose all the brake fluid. Lovely and friendly assistant to help bleed the brakes. (My wife played this part. I'm lucky she is always willing to help) Here is what I did: 1. Raise the car, support w/stands. 2. Remove the wheels. 3. Using the 11mm and 14 mm flare wrenckes disconnect the rubber line from the metal line. If you need to change pads and rotors, now is a good time. 4. Using the 19 mm socket, remove the caliper hold down bolts and the caliper. 5. Clean of the caliper as good as possible. 6. Use air gun to remove the pistons. Make sure you have rags in between them to avoid damage. 7. On mine, only one piston came out using the air. So I removed the dust seal from the one that stayed in the caliper, and then used the two flat head screwdrives to pull the piston out. If you do not have access to air, use this method to remove the pistons. 8. Clean off the pistons and the cylinders. Mine were dirty. Luckily, no pitting or corrosion was present. If any is found, replacement calipers are in order. 9. Remove the old seal from inside each side cylinder. I used one of the flat head screwdrivers. Be careful not to score the inside of the cylinder. 10. Polish the pistons, if needed. Mine had some brown gunk adhered to them near the outer portion. I used the polishing flap wheel. (no sand paper only 3M polishing (like an SOS pad) and canvas.) It took that stuff right off without scoring the piston. 11. Insert the new piston seal in each cylinder. Use new, clean brake fuid to lube the seal. 12. Install the new dust shield on each piston. Note the orientation of the seal in relation to how it seats on the caliper. 13. Lube the pistons w/ brake fluid. 14. Insert one piston in to a cylinder. It is hard to press in. MAKE SURE THE MIDDLE LARGER "C" SHAPE IS FACING UP IN RELATION TO HOW THE INSTALLED CALIPER IS ON THE CAR. 15. Used the long wide flat piece of metal as a press. One hand on either side of the metal or caliper. It is your choice on how to do that. I used an old wood stove with the cover off as a platform to press the caliper and piston. 16. Repeat step 15 for the other piston. 17. Use the old dust shield as a helper to press the dust sheild to the caliper. Use the channel lock pliers to seat the dust seal. 18. Make sure all is seated well. 19. Install the caliper, install the brake pads, reconnect the brake lines. 20. Loosen the bleeding screw with the 9mm flare wrench. 20. Remove the air block from the M/C. 21. Wait for brake fluid to begin dripping out of the bleeder. Then tighten it. 22. Have lovely assistant press and release brake pedal, under your instruction while you loosen and tighten the bleeder, until all air is removed. 23. Refill Master cylinder. 24. Repeat steps 3-23 for remaining calipers.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K Last edited by rrgrassi; 07-27-2009 at 12:19 PM. |
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Second set of pics
I wish you could do more than 5...
The job was not real bad. Took about 3 hours total since I had to clean and polish the pistons, and take pictures. The repair kits came from Phil.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
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There is a specific angular orientation required when the piston is inserted into the bore. If you look at the piston, it's not uniform on the pad contact face.
This is a point that is usually missed when the caliper is rebuilt at home. Furthermore, installing the heat shield (front calipers) is next to impossible without the proper tool. |
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So
If the Piston is stood Vertical, on the Pad contact surface,the Barrel/Cylinder
of the Piston will be slightly like the leaning tower of Pizza?
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'84 300SD sold 124.128 |
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Quote:
The contact between the piston face and the pad is not uniform. M/B desires a specific loading pattern on the pad, presumably to eliminate squeal. From memory, the angular relationship is 20 degrees of vertical..........but, it's been a long time. I don't do them anymore. |
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The pistons were not in any particular angle that I could see. I bet these were replaced by the PO at one time. No records though. I did not line up the pistons vertically either.
So far no squeaks, binding, or trouble stopping.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
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Quote:
Here is a pic, hope it is readable
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84 300D, 82 Volvo 244Gl Diesel |
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Well now, I will have to check that out. Probably this upcoming weekend.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
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A tip to help extract the pistons: Before removing the caliper from the car, take the pads out, then push the brake pedal a few times until the pistons seat against the rotor. (Once they're touching the rotor, they're almost completely out). Now take the caliper off the car and see how easy it is to get the pistons the rest of the way out.
Also, if you're using compressed air, be sure to cover the entire thing with a cloth rag. With compressed air, the pistons will make a "pop" sound as they come out of the bore, and at the same time will release a small puff of brake fluid "mist". You do not want to breath this mist!
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'98 E300 turbodiesel |
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If they don't squeal, I wouldn't worry about it...........you're not going to pull the piston to rotate it............but a note in the procedure might be nice............
Last edited by Brian Carlton; 07-27-2009 at 12:17 PM. |
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It's added!
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K Last edited by rrgrassi; 07-27-2009 at 12:26 PM. |
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