Rear brake excessive wear

Maintenance advice to keep your Spider in shape.
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seabeelt
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Joined: Tue Feb 19, 2008 4:22 pm
Your car is a: Fiat Spider - 1971 BS1
Location: Tiverton, RI

Rear brake excessive wear

Postby seabeelt » Sat Sep 02, 2017 10:21 am

Thought I would put this out there and see if anyone else has encountered this

Rear brakes seem to wear out about every 2500 miles.

A couple years ago I went through the entire system after a MC failure. Put new hoses on each of the calipers along with caliper rebuild kits , new rotors and pads. Only hose I didn't change was the center one that feeds the distribution block over the rear axel

Last summer I had to replace the rear brakes as the right rear was down to the rivets. So I thought must be the caliper as the left rear was worn, but certainly not like the right rear. Rebuilt the caliper again paying special attention to the piston seals and even broke the whole caliper down to clean ad grease the e-brake portion. Replaced rotors and pads both sides

So now here I am approx 2500 miles later and the right rear is down to the rivets and left rear is worn but not like the right rear just like before.

I'm wondering if that hose over the axel has something to do with it? Proportioning valve?? new MC ????? They should NOT be wearing that fast. By contrast the fronts a wearing evenly and still show good pad depth after approx 5-6 k miles as you woul expect

Got my new CD3s all dusty Grrrrrrr

Any thoughts from the considerable brain trust here???
Michael and Deborah Williamson
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current

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lglade
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Your car is a: 1984 Pininfarina
Location: Mukilteo, WA

Re: Rear brake excessive wear

Postby lglade » Sat Sep 02, 2017 11:02 am

For cars working normally, the front brakes do about 70% of the braking due to weight transfer. So if your rears are wearing out that quickly, then I'd want to know if the fronts are truly functioning properly. If you jack up the rear end, and put the transmission in neutral, can you easily turn the rear wheels? You should be able to tell if the rear brakes are dragging.
Lloyd Glade- Mukilteo, WA
1984 Pininfarina Spider Azzurra
1962 Fiat 500D - wife's car
2015 Subaru Outback
2017 Ford Focus RS

DieselSpider
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Joined: Wed Dec 24, 2014 10:21 pm
Your car is a: 1978 124 Spider with Isuzu Turbo Diesel

Re: Rear brake excessive wear

Postby DieselSpider » Sun Sep 03, 2017 12:09 pm

2,500 miles would indicate either the parking brake is set too tight or the hose you did not replace needs to go. The rears must also be showing signs of heating if your going through them so fast which is also not good for the diff, axle bearings or the tires.

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nelsonj
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Your car is a: 1972 Spider 124

Re: Rear brake excessive wear

Postby nelsonj » Mon Sep 04, 2017 2:17 am

My parking break locked up and wore through my pads and one rotor (passenger side) in no time. I later had to rebuild a rear break cylinder. I had a new parking break cable put on and that solved the issue. However, I don't really trust my parking break after that and I tend to use 2nd gear rather than the break.

I've put well over 10K miles on the breaks after that without issue.

Good luck.
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Simi Valley, California
Spider 1800
Romans 10:9

klweimer
Posts: 550
Joined: Tue Mar 27, 2012 7:45 am
Your car is a: 1982 Spider 2000
Location: Arvada, Colorado

Re: Rear brake excessive wear

Postby klweimer » Mon Sep 04, 2017 11:35 am

Great point about the front brakes not working well, causing the rears to do all the work. I would bleed the heck out of the fronts and make sure the master cylinder is fully bled too. You might want to pull the MC and bench bleed it. I would also pull the rear caliper pistons and make sure the guts inside the piston are clean and working well. There's a fairly complex ratchet mechanism inside the rear pistons that makes the parking brake system work.
Kirk

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seabeelt
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Your car is a: Fiat Spider - 1971 BS1
Location: Tiverton, RI

Re: Rear brake excessive wear

Postby seabeelt » Mon Oct 23, 2017 3:53 pm

Well, I replaced the center hose and found a rusted metal line starting to leak to boot. Changed both. Brakes seem to function much better. That center rear hose was definitely plugged. Collapsed from the inside. Couldn't see or blow through the hose at all. Put on new pads and rotors of course. Think I still have a small air bubble in the right rear caliper, but overall a satisfactory job, and I didn't break anything either 8) Did find that the compensator arm bushing where it moves at the axel is missing. Guess I will have to make something for that as I haven't seen anything on any of the vendor sites
Michael and Deborah Williamson
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current


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