Volvo Owners Club Forum - View Single Post - V70 Brakes:

Tailslide uk · Mar 12th, 2011, 21:24

I posted a bit of this over in the "disaster" thread. It should be here as this thread is active. My Volvo is a 98 V70, but uses the same system. My parking brake shoes seperated exactly like the photos in the disaster thread, but thankfully without the assciated damage.

My mechanic is ex-volvo ML and now works at an independent. His take on this issue is that you can replace shoes until the the end of time, but you are not addressing the root cause of the problem.

The shoes are bonded to the carriers with an epoxy. The epoxy has a temperature limit. If the shoes get above this limit, the epoxy goes soft and lets go of the shoe. The brakes are designed to work only when the vehicle is stationary or in an emergency. In other words, they should not wear (much). According to him, the culprit is the cable. The rubber seals on the end fail and the inside of the cable goes dry/dirty/rusty. It seems to release when you drop the lever, but the cable either has to work its way back out of the sheath or never quite does. If the brake shoes are just lightly making contact with the inside of the drum, they generate heat and then delaminate.

According to his theory, jack up the wheel and turn it. If the shoes is making ANY contact with the drum (with the parking brake off), remove the cable from its sheath and sort it with a good cleaning and grease. If the cable does not allow the brake to completely release, the shoes will part company in a few hundred miles every time. The spring force pulling the cable out of the sheath when the parking brake is released is not very high. If the shoes are still rubbing the drum when the spring force and cable drag reach equilibrium, bye - bye shoes. The inside of this drum just has no way to get rid of the heat and it builds up until the epoxy fails.

Just my 2P. He seems to know his stuff and has saved me a pile of £££ over the last 110K since I swithced to him. Obviously this step is in addition to replacing the shoes. He also recommended (as stated above) driving a few hundred meters once a week with the parking brake lightly applied to dry everything out and knock off the rust.

Paul
__________________
Go fast, turn hard...

Mar 12th, 2011, 21:24	#51
Tailslide uk New Member Last Online: Mar 20th, 2011 17:12 Join Date: Mar 2011 Location: Berkshire	More info - FWIW I posted a bit of this over in the "disaster" thread. It should be here as this thread is active. My Volvo is a 98 V70, but uses the same system. My parking brake shoes seperated exactly like the photos in the disaster thread, but thankfully without the assciated damage. My mechanic is ex-volvo ML and now works at an independent. His take on this issue is that you can replace shoes until the the end of time, but you are not addressing the root cause of the problem. The shoes are bonded to the carriers with an epoxy. The epoxy has a temperature limit. If the shoes get above this limit, the epoxy goes soft and lets go of the shoe. The brakes are designed to work only when the vehicle is stationary or in an emergency. In other words, they should not wear (much). According to him, the culprit is the cable. The rubber seals on the end fail and the inside of the cable goes dry/dirty/rusty. It seems to release when you drop the lever, but the cable either has to work its way back out of the sheath or never quite does. If the brake shoes are just lightly making contact with the inside of the drum, they generate heat and then delaminate. According to his theory, jack up the wheel and turn it. If the shoes is making ANY contact with the drum (with the parking brake off), remove the cable from its sheath and sort it with a good cleaning and grease. If the cable does not allow the brake to completely release, the shoes will part company in a few hundred miles every time. The spring force pulling the cable out of the sheath when the parking brake is released is not very high. If the shoes are still rubbing the drum when the spring force and cable drag reach equilibrium, bye - bye shoes. The inside of this drum just has no way to get rid of the heat and it builds up until the epoxy fails. Just my 2P. He seems to know his stuff and has saved me a pile of £££ over the last 110K since I swithced to him. Obviously this step is in addition to replacing the shoes. He also recommended (as stated above) driving a few hundred meters once a week with the parking brake lightly applied to dry everything out and knock off the rust. Paul __________________ Go fast, turn hard... __________________ Go fast, turn hard... Last edited by Tailslide uk; Mar 12th, 2011 at 21:27.