DIY: Parking Brake Failure Inspection ('98 S70 as ref')

[QuirkySwede]

ISSUE: Need for parking brake system inspection. OEM components are prone to various degrees of failure due to age, exposure to elements, and heat which could affect drive-ability and control.

CONSEQUENCES: One or both rear wheels could lock up immobilizing vehicle when parked, or causing loss of control if it occurs while moving.

RECOMMENDATION: Perform simple "adjuster," "drag," and "visual" inspections via OEM tool kit and jack. Plan for inspection of rear (parking) brake shoes as part of next preventative maintenance. Add system inspection to appropriate service interval and any rear wheel service (e.g. brakes, bearings, tires, pads, brake fluid flush, etc.).

NOTES: I have already seen this failure on two Volvo S70 cars (GLT and T5) where the right-side parking brake cable failed in the exact same spot and noted similar signs on recent junkyard cars of similar vintage. One left the rear wheel locked up after starting the car when the parking brake would no longer release. Snapped cable at the lever end was also encountered. Both vehicles also had the parking brake drum shoes pad material coming loose, possibly exacerbated by heat build up, due to a dragging parking brake, due to it not fully releasing, due to a binding cable, due to cracked junction. Chain of events could have been worse. Others have had similar problems. All three (cable bracket bend, adjuster, and shoes) should be inspected. The following is written based off the 1998 Volvo S70; other models similar.

TOOLS NEEDED: Flat tip screw driver, 13mm* metric socket with socket wrench, 19mm* deep socket, OEM lug bolt wrench, torque wrench, OEM jack, T50 torx bit (parking brake adjuster bolt), and 10mm* metric deep socket or box end wrench. ( * Having a full set with is recommended.)

DISCLAIMER: Working on a vehicle can result in injury or death. If you are not comfortable with managing this, please leave the work to a qualified and reputable mechanic and or shop to inspect and or repair.

CONTENTS:
A. CABLE BRACKET BEND INSPECTION
B. ADJUSTER INSPECTION
C. PARKING BRAKE SHOE INSPECTION
D. PARKING BRAKE CABLE REPLACEMENT
E.DIT: Adjustment notes

A. CABLE BEND INSPECTION
1. With car parked and PARKING BRAKE OFF, get down and look at where the cable bolts to the frame just forward of the rear wheel. If it makes an angular bend versus a curve or shows any signs of cracking, do NOT apply parking brake as it might bind internally preventing the brake from releasing, immobilizing the car. Cable casing should flex in a distributed fashion when flexed gingerly by hand, not pivot at one point. Even a partial release that still drags could cause the drum brake inside the disc brake's hub to overheat and fail, potentially locking up the wheel while moving.

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2. REMEDY: Replace brake cable. Seized cable may need to be severed (bolt cutters, saw, etc.) in order to relieve enough tension to remove disc/drum from axle to access drum shoes and end of cable. Cable replacement requires the removal of the shifter-parking brake console; removal of wheel, caliper, disc+drum, and shoes on affected side; and removal of rear door lower trim and either removing rear seat bottom or unbolting front seat and tilting forward (my preference) in order to raise carpet enough to remove and re-route new cable. The plastic covers over the seat bolts slide forward to remove. (More under part D.)

B. ADJUSTER INSPECTION
1. With car parked and PARKING BRAKE OFF, open center arm rest between driver and passenger seats. Use a flat-tipped screwdriver to remove parking brake adjuster access panel. (See Center Console Removal part 6 as well as V70 S70 C70 Center Console Light.) Note alignment of equalizer bar spanning the two parking brake cable cams. Apply parking brake slowly and smoothly, do not jerk it abruptly, and be careful not to raise it so high as to hit or damage the plastic at the top where it meets the parking brake lever's boot. Note alignment of equalizer bar again. If at either position the equalizer bar is not oriented straight left-to-right, a cable and or brake shoe has likely failed and further inspection is needed. If parking brake takes more than 4 to 5 clicks to firmly engage, then it is possible that there is failure on both sides' shoes or adjustment is needed, and further inspection is needed. From memory, the adjuster bolt requires a T50 torx bit; simple to verify by raising the armrest, popping the cover off, and looking, possibly with a mirror.
2. REMEDY: A further inspection including part C below is needed to determine the cause and appropriate action.

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C. PARKING BRAKE SHOE INSPECTION
1. Park car on hard, level concrete surface that can support jack. Unlock doors and lower front windows. Do NOT apply parking brake. Chock both front wheels and opposing rear wheel, front and rear. Break each lug bolt free then snug, one after another. Using OEM jack or other suitable arrangement, raise rear wheel until it no longer touches the ground. Spin rear wheel and note any brake drag. Remove bolts (19mm) and wheel. Remove both rear caliper bolts (13mm) and remove caliper off to side, just enough for disc to clear, and rest in such a manner (e.g. on a box) so as to induce minimal strain and bend on the brake line. Do NOT allow caliper to hang. Rotate disc+drum and note any drag, which if present is due to the shoes. Carefully apply parking brake from non-lifted side and then try to rotate disc+drum, which if it rotates indicates a snapped brake cable, missing shoe pad material, or need of shoe adjustment (least likely). If disc+drum is immobile, release parking brake and check for drag again. Remove disc+drum to hub pin between bolt holes with a deep 10mm socket or box end wrench. With parking brake disengaged, remove disc+drum by pulling directly away. If it has no give, it is likely rusted to the hub and will require striking the drum, NOT the disk, with a hammer from alternating directions (star pattern is good) with increasing force until it frees. If it gives a little and then stops, it is likely impeded by the drum brake's shoes whose tension will need to be relaxed by rotating the adjuster hole (opposite the pin hole) to about 11:30, sticking a flat tipped screwdriver in and rotating it down repeatedly until it stops (helps to shine light in through adjacent lug bolt hole to sight adjuster and center in on it), but if the adjuster has been flipped, it will need to be rotated down (which ever direction removes drag or does not lock drum). Both brake shoes should have friction material of consistent thickness firmly bonded to full arc of metal brake shoe backing. Replace both shoes on both sides should any shoe fail inspection (do not toss in trash, save for "core" when buying new shoes).

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2. REMEDY: Replace drum shoes (and springs if appropriate). (See Ozark Lee's Parking Brake Replacement for more photos) Detach spring via hook at one end and set aside. Remove adjuster noting orientation and set aside. Pull shoes out to sides to free from clip, the rotate one towards you to relieve tension on lower spring, unhook, and remove both shoes. Remove any rust from contact areas between hub, disc+drum, and wheel with a brass brush. Thoroughly clean all parts as necessary and allow to dry. Replace parking brake cable at this time (tension will need to be relieved at parking brake adjuster, cable end removed from lever cam, then removed from drum lever by bending retaining tab out just enough for cable stop to pass through). Check drums and take to machine shop to have turned (often ~$8) if needed and if it can be done without exceeding spec; otherwise replace with new (seen for ~$25 each; caliper adjustment will likely be needed if new disc+drum is significantly thicker than worn one). Smear appropriate areas with grease to ensure smooth actuation and release of parking brake shoes with out binding, avoiding excess that could foul drum shoes. Continue reassembly in reverse order of dis-assembly, centering shoes on backing plate. With disc+drum installed and pin tightened, turn adjuster until shoes drag, the back off 4-6 clicks, apply then release parking brake, then repeat procedure to confirm adjustment as shoe might recenter. Torque rear brake caliper bolts to spec. Remove any corrosion from wheel bolts with wire brush. Snug wheel bolts in star pattern, lower wheel until tire touches ground, snug more, lower off jack and torque to spec in star pattern. Consider applying parking brake slowly and enough to tension the shoes in open parking log at about 5 mph (walking pace) for about 20 feet keeping button pressed in, forward, then backward back, then rechecking drum adjustment on each side followed by lever adjustment under armrest (see notes at end). Parking brake should be engaged with around 5 clicks at the lever and wheels should rotate with no drag when released. NOTE: Unlike some drum brakes, the Volvo parking brake system is NOT self-adjusting and MUST be MANUALLY ADJUSTED to compensate for shoe wear. If drag was not present when only disc+drum was installed and adjusted, but is when wheel is later rotated, suspect brake caliper (time since last brake fluid flush?).

D. PARKING BRAKE CABLE REPLACEMENT (right side shown, left similar)
Additional tools may be needed. Disconnect battery to avoid any SIPS or SRS issues. Remove center shifter console (see part B above). Remove rear brake shoes as outlined above. Remove lower door trim on frame by first removing torx screw at rear seat belt anchor, pulling out of lower clips, and work out of cover on pillar between front and rear doors. Slide plastic cover over front door-side bolt forward. Remove front two seat bolts. Release pins at rear of front passenger seat hinges and fold down flat. Remove rear two seat bolts and pivot seat forward so head rest is under dash and prop up as needed. Slacken parking brake adjuster bolt (equalizer) as needed counting turns for reassembly. Remove cable end from parking brake lever cam. Pull cable at drum brake, pry up catch just enough to slide cable end out of shoe lever. Tie string to cable end at parking brake lever. Work carpet up and use small pry bar to pop plastic cable routing loop up off barbed pin noting which side it runs on. Unbolt cable from frame on underside of chassis just forward of rear wheel. Pop cable grommet out of rear foot well and push front part of cable out working and guiding it under the carpet and padding, then draw out from rear. Installation reverse of removal. Remember to depress retaining catch that holds cable end in place on brake shoe lever, guide cable back into channel in padding under carpet, re-attache the retaining clip in the footwell, and torque all bolts to spec.

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E.DIT: I think I should also note that there are two ways the parking brake is adjusted: via the "spur" through the hole in the disc+drum, and via the bolt at the equalizer ("cable") on the parking brake lever. In use, the material at the bottom of the shoe wears as they swing out when the lever is applied. If the bolt is adjusted to account for wear, the "spur" should checked, tested as described, and rechecked to always make sure the parking brake fully dis-engages so there is neither drag nor subsequent heat build up. I do NOT have a spec handy for the parking brake adjustment such as "tighten until X wheel(s) drag and then back off Y turns." FYI, many cars with rear drum brakes use a hydraulic cylinder on one end (e.g. top, foot brake) and a cable on the other (e.g. bottom, parking brake, self adjusting), that results in a more even wear of the shoes without the need for manual adjustments provided the rest of the components are in spec (e.g. ratcheting auto-adjuster not locked up from dirt, grime, corrosion). Those system's pivots are fixed whereas the Volvos allows the shoes to float, slide, even rotate quite a bit making for a less robust "emergency" brake while moving and highlight the need to make sure they are centered on the backing plate then re-adjusted after a couple used (described above) to account for any repositioning of the shoes from "re-settling." As such, don't be surprised if you hear a "pop" when applying the parking brake if the car is trying to roll the opposite direction from the last time it was applied -- shoe rotating a bit in the drum until they hit the stop on the other side.

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(Write up and photos are not meant to be ideal, merely sufficient. Drive safe!)

[matthew1]

Very nice, QS. I'll be doing this myself. Scheduled for inclusion in the Repair Database.

[abscate]

While it is tempting to do the easy adjustment at the handbrake/parking brake/emergency brake handle the brake has to be adjusted at the wheels first. Do an adjustment, apply brake several times to re center shoes. And then adjust one more time. My 1999 had the adjusters in slightly different places on the drum, I will link to thread. Don't be afraid to have a bit of drag, you only want 2-3 teeth of slack after the shoes are tight to get good brake action.

I trailer a lot of boats so having my brake work keeps my car dry.

[matthew1]

Added to VRD. QuirkySwede, your account was added to MVS Contributors group for this fine writeup.

[Warren561]

Wonderful write-up. Thanks for sharing it!

[cn90]

I covered similar Parking Brake issues in another thread from a year ago:

DIY: 1998 Volvo S70 GLT Parking Brake Tips/Tricks

My Parking Brake Cable cracked at the classic locations, I knew that replacing the Parking Brake Cables was a PITA job, so I did the temp fix until I have time to do the proper fix (which is replacing both Parking Brake Cables). So far so good with temp fix.

- I added some oil at the cracks to free up the cables.
- Cover the cracks with some grease, then add rubber hose/zip ties as shown:

[BlackThunder]

Awesome! My parking brake shoe broke a couple of years ago. That was scary, thankfully I was only going about 15mph when it happened. Great write up. I'll wait until it's warmer to attempt this repair. It is time.

Dustin

[rmmagow]

These instructions/techniques would be pretty much the same for a 98 V70 AWD? My ebrake handle pulls up with very little resistance and zero Ebrake function. I'm hoping something popped off rather than a snapped cable. Pretty expensive parts to fix this. I adjusted the thing at the canter console basically all the way and no change. I'll be sure to pull the discs first and have a good root around. They did used to work at some point in the past couple of years.

[scot850]

I did a write up on this several years ago, when I did my 98 V70XC. AWD is a little more complicated but otherwise mostly the same. I had to loosen the rear sub-frame mounts to allow the cable to be removed just in front of the rear wheels. It is also riveted from above to hold it in place at that point. I used small bolts and nuts instead as I couldn't get the rivet gun in from above without fully removing dropping the frame.

Also, the 98 had no small inspection hole in the rear drum. You have to access the adjuster though one of the lug nut holes. Adjuster is at approx. 7-8pm looking at the LHR, and 4-5pm on the RH rear.

Otherwise, awesome write up!

Neil.

[rmmagow]

Thanks much. It is truly a mess back there, I need virtually everything. Attempting to determine if my cables are still OK. Nasty and totally worn shoes and I'm not getting much action when I had my wife work the ebrake handle. Hope the cables are OK and I'm trying to figure out a way to be sure as I am too wary of heavy undercar work on an old and failing back.