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DIY Front Disc Pads, Inner Oil Seals, etc
My front disc brake slide pins were sticking out past the boss less than .250″. When new the pin sticks out about .625. Mx manual section 12 page 17 &18 says to pull the wheel and inspect, So, that’s what I did. The inner pad had about .200″ of fiction material remaining. When new it has .910″. The outer had .300″ remaining. When new it has .570″.Since these Rockwell/Meritor disc brakes are a single (inner) piston design, the inner pad wears much faster than the outer. That’s why the inner pad is so much thicker than the outer when new.While I had the caliper off:Also removed hub/rotorcleaned bearings, slide pins, bushings, replaced o-rings on pinsLubed caliper, slide pin, bushings, slack adjuster, tie rod, king pinChanged frt right inner oil seal w/Scotseal SKF # 35066 = Prevost# 610870Changed outer gear oil hubcap w/Road King 343-4024 = Stemco 343-4024 = Prevost# 611252replaced brake pads w/new – Meritor# KIT15615PM or SR27017173 per wheel, or Meritor# KIT15625 per axle.replenished gearoil with Amsoil SVG 75w-90reassembled everythingset wheel bearing pre-load/end play to .002”adjusted braketorqued lugs nuts 450 ft lbsTest drove itWill do the same to the left front soon. Drive and tag axle brakes still have plenty of meat.Don’t tackle this job if you don’t like getting dirty 🙂 -
9 Replies
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2 fingers worth of wear, or 1″. Piston has to be adjusted all the way back in so the new pads will fit over the caliper.
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My index finger points at the poppet
My middle finger at the pawlMy thumb at the adjusterPer the mx manual on how to grease the calipers, adjust the brake, and check for proper automatic slack adjuster operation:a) remove the caliper poppet fitting that’s located half way between the 2 grease fittings.b) pump Meritor pt# A1779W283, NLGI#1 grease, into the 2 grease fittings until fresh grease comes out the poppet fitting hole.*****Have the front wheels chocked, have enough air in the brake tanks and release the parking/spring brakes*****c) release the pawl (hold it out) on the slack adjuster and adjust or loosen it(cw=lengthen stroke) fully which is about 4 or 5 360 turns of the adjuster on the end of the slack adjuster. This will force excess grease out of the poppet fitting hole.d) reinstall the poppet valve/fittinge) re tighten(ccw=shorten stroke) of slack adjuster fully until pads are clamping the rotor, then release the pawl again and loosen/release(cw=lengthen) stroke 1/2 to 3/4 turn.f) set parking brake, remove chocks -
Good work Don. Thanks for the detailed photos and explanation, feels like I was there.
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Thanks Luc,
Do you feel dirty 🙂
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Ha Ha! I almost said that.
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My memory must be terrible. Replaced steer axle pads a year or so ago (Rockwell/Meritor), ordered from Prevost. I don’t remember a thickness difference between inner and outer – but I guess there was. Also don’t remember what looks like a tone ring on the back side of rotor(s). No ABS on mine, guess that was an option back then (95 chassis)?
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My 95 chassis/96 Liberty #331 doesn’t have ABS either, but it may have been an option in 1995.
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My 92 has the same proximity sensor flags, and i have an ABS dash light that comes on when i turn the key on. I have never tested to see if it works, nor do i plan to.
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Thanks for the write-up Don! I’ll be referencing this later.
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