Volvo Community Forum. The Forums of the Volvo Owners Club

Forum Rules Volvo Owners Club About VOC Volvo Gallery Links Volvo History Volvo Press
Go Back   Volvo Owners Club Forum > "Technical Topics" > S40 / V40 '96-'04 General

Notices

S40 / V40 '96-'04 General Forum for the Volvo S40 and V40 (Classic) Series from 1995-2004.

Information
  • VOC Members: There is no login facility using your VOC membership number or the details from page 3 of the club magazine. You need to register in the normal way
  • AOL Customers: Make sure you check the 'Remember me' check box otherwise the AOL system may log you out during the session. This is a known issue with AOL.
  • AOL, Yahoo and Plus.net users. Forum owners such as us are finding that AOL, Yahoo and Plus.net are blocking a lot of email generated from forums. This may mean your registration activation and other emails will not get to you, or they may appear in your spam mailbox

Thread Informations

Unexpected Brake failure.

Views : 673

Replies : 10

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old May 7th, 2019, 17:41   #1
Torbuck
New Member
 

Last Online: Nov 20th, 2019 17:02
Join Date: Feb 2019
Location: Brighton
Default Unexpected Brake failure.

Hey all.

Have already had a bit of a read up and seen some good advice regarding correct bleed method but I am seeking more a diagnosis is possible by explaining my symptoms.

Long and short of it is the pedal as of today travels all the way down before any braking at all followed by a max 10% of yesterday’s brake pressure.

There was very little fluids in the reservoir so I topped it up today but apart didn’t I haven’t taken callipers off so not given air the chance to get in?

It’s my daily car so I’m gonna be outside until it’s fixed If I can be. Help please.
Torbuck is offline   Reply With Quote
Old May 7th, 2019, 18:37   #2
pierremcalpine
Premier Member
 
pierremcalpine's Avatar
 

Last Online: Jan 3rd, 2024 15:43
Join Date: Feb 2012
Location: Toronto Canada
Default

Quote:
Originally Posted by Torbuck View Post
Hey all.

Have already had a bit of a read up and seen some good advice regarding correct bleed method but I am seeking more a diagnosis is possible by explaining my symptoms.

Long and short of it is the pedal as of today travels all the way down before any braking at all followed by a max 10% of yesterday’s brake pressure.

There was very little fluids in the reservoir so I topped it up today but apart didn’t I haven’t taken callipers off so not given air the chance to get in?

It’s my daily car so I’m gonna be outside until it’s fixed If I can be. Help please.
Well, that's problematic, isn't it?
First step would be to inspect all four calipers to make sure you don't have a leak. I recently had one on one of the rear calipers at the back of the handbrake assembly. Spotting the leak would be easy: just look for dampness. All four calipers should be totally dry. Then inspect the master cylinder to make sure no external leaks are visible.

Also inspect to make sure pads are still intact on all four calipers. This may require shining a flashlight in behind each caliper, etc.

I wonder if you let the fluid get so low that air got into the master cylinder?

It really doesn't take much air for you to experience degradation in pedal feel.

Need more info: had brake work been done recently? How old are pads and rotors?
__________________
2003 V40 1.9T B4204T4, 197,000miles (sold but alive!), 2004 S60 2.5T, 160,000miles, 2010 V70 3.2, 125,000miles, 2002 V70XC 2.4, 175,000miles

Click here for my x40 and V70 P3 repair guides
pierremcalpine is offline   Reply With Quote
Old May 7th, 2019, 21:44   #3
gazO2V40T4
Premier Member
 
gazO2V40T4's Avatar
 

Last Online: Feb 14th, 2021 12:50
Join Date: Jul 2013
Location: Penrith, cumbria
Default

Quote:
Originally Posted by Torbuck View Post
Hey all.

Have already had a bit of a read up and seen some good advice regarding correct bleed method but I am seeking more a diagnosis is possible by explaining my symptoms.

Long and short of it is the pedal as of today travels all the way down before any braking at all followed by a max 10% of yesterday’s brake pressure.

There was very little fluids in the reservoir so I topped it up today but apart didn’t I haven’t taken callipers off so not given air the chance to get in?

It’s my daily car so I’m gonna be outside until it’s fixed If I can be. Help please.
I would suggest one off your brake pipes has corroded to the point of failure most likely one of the rear pipes
__________________

2002 V40 T4
17" Arcadia's ,Boost Gauge ,Forge Dump Valve And Blanking Plate ,Front Upper Strut Brace
gazO2V40T4 is offline   Reply With Quote
Old May 7th, 2019, 22:25   #4
Torbuck
New Member
 

Last Online: Nov 20th, 2019 17:02
Join Date: Feb 2019
Location: Brighton
Default

Purchased the car in March but have receipts and visible proof that the rear Caliper had been replaced. The previous owner didn’t service it in 3 years prior to that it’s has fsh from a Volvo from new. I

Did a check today on lines and couldn’t see anything indicating s leak but could t find one. I’m gonna bleed the new caliper tommorow as the nipple will be easy to undo, dubious about the rest but as mentioned could a low resivior result in ait getting in? I thought it was a vacuum?

Cheers for the replies lads
Torbuck is offline   Reply With Quote
Old May 7th, 2019, 23:16   #5
XC90Mk1
Premier Member
 

Last Online: Feb 16th, 2024 14:43
Join Date: May 2018
Location: Na
Default

Quote:
Originally Posted by Torbuck View Post
Purchased the car in March but have receipts and visible proof that the rear Caliper had been replaced. The previous owner didn’t service it in 3 years prior to that it’s has fsh from a Volvo from new. I

Did a check today on lines and couldn’t see anything indicating s leak but could t find one. I’m gonna bleed the new caliper tommorow as the nipple will be easy to undo, dubious about the rest but as mentioned could a low resivior result in ait getting in? I thought it was a vacuum?

Cheers for the replies lads
I would have thought low fluid level would result in air in the ststem yes.
XC90Mk1 is offline   Reply With Quote
Old May 8th, 2019, 01:26   #6
canis
Non Fragile
 
canis's Avatar
 

Last Online: Oct 13th, 2023 06:46
Join Date: Apr 2010
Location: Chadderton, Oldham
Default

Quote:
Originally Posted by Torbuck View Post
Hey all.

Have already had a bit of a read up and seen some good advice regarding correct bleed method but I am seeking more a diagnosis is possible by explaining my symptoms.

Long and short of it is the pedal as of today travels all the way down before any braking at all followed by a max 10% of yesterday’s brake pressure.

There was very little fluids in the reservoir so I topped it up today but apart didn’t I haven’t taken callipers off so not given air the chance to get in?

It’s my daily car so I’m gonna be outside until it’s fixed If I can be. Help please.
You've got a leak somewhere. Brake fluid never needs topping up, it's an entirely closed system. If you've lost fluid it's because it's leaked out. You need to find the leak because it'll jet onto metalwork, and corrode it like nobody's business.

The place to start is the flexible hoses which attach to the calipers. They do burst, had it happen to me a couple of months back.

Easiest way is to look at the floor, the hydraulic oil will form rainbows on wet ground, a puddle of oil on dry ground. That should help you find the leak. Trace back the path of the oil, fix the leak. Wash the oil off any bodywork with copious amounts of water. A garden hose is ideal, but it can be a wet job.
canis is offline   Reply With Quote
Old May 8th, 2019, 14:07   #7
pierremcalpine
Premier Member
 
pierremcalpine's Avatar
 

Last Online: Jan 3rd, 2024 15:43
Join Date: Feb 2012
Location: Toronto Canada
Default

Also a easier to check for leaks if someone is there to press brake pedal while you inspect underneath.
__________________
2003 V40 1.9T B4204T4, 197,000miles (sold but alive!), 2004 S60 2.5T, 160,000miles, 2010 V70 3.2, 125,000miles, 2002 V70XC 2.4, 175,000miles

Click here for my x40 and V70 P3 repair guides
pierremcalpine is offline   Reply With Quote
Old May 8th, 2019, 15:13   #8
cheshired5
Premier Member
 

Last Online: Dec 26th, 2021 14:42
Join Date: Dec 2013
Location: Crewe
Default

Quote:
Originally Posted by canis View Post
You've got a leak somewhere. Brake fluid never needs topping up, it's an entirely closed system. If you've lost fluid it's because it's leaked out.
Not at all.
It's fluid pressure which pushes the caliper piston onto the back of the brake pads to maintain braking force.
As the pads wear down, the piston needs to travel further out of the caliper and the brake fluid level will fall accordingly to maintain braking pressure.
Occasional brake fluid top ups can be a normal part of maintenance but are usually unnecessary if the fluid is changed every 2 years.

OP needs to check for pad thickness, caliper operation, air in the system and fluid leaks but low fluid isn't automatically caused by a fluid leak.
__________________
2002 S60 SE D5 Manual
209000 miles
cheshired5 is offline   Reply With Quote
Old May 9th, 2019, 12:08   #9
canis
Non Fragile
 
canis's Avatar
 

Last Online: Oct 13th, 2023 06:46
Join Date: Apr 2010
Location: Chadderton, Oldham
Default

Quote:
Originally Posted by cheshired5 View Post
Not at all.
It's fluid pressure which pushes the caliper piston onto the back of the brake pads to maintain braking force.
As the pads wear down, the piston needs to travel further out of the caliper and the brake fluid level will fall accordingly to maintain braking pressure.
Occasional brake fluid top ups can be a normal part of maintenance but are usually unnecessary if the fluid is changed every 2 years.

OP needs to check for pad thickness, caliper operation, air in the system and fluid leaks but low fluid isn't automatically caused by a fluid leak.
Alright, yes you are absolutely correct. I've never actually measured, but I'd expect the relevant slave cylinder displacement to be only marginal compared to the size of the reservoir pot.

Also the level would drop over time and not suddenly all at once, in which case the fluid level warning light would've been flashing on around sharp bends for considerable time. I kinda presumed the OP would've said so if that was the case, so I'm guessing it's all suddenly dropped all at once which would strongly imply a leak

Nevertheless, I do agree the level will appear to be "consumed" through use, due to gradual wear. I thought it was bad practice to top up this usage? Otherwise when you replace the pads, when the piston is forced back to top, all the extra fluid overflows....?

Anyway thanks for the correction.
canis is offline   Reply With Quote
Old May 9th, 2019, 12:43   #10
cheshired5
Premier Member
 

Last Online: Dec 26th, 2021 14:42
Join Date: Dec 2013
Location: Crewe
Default

Quote:
Originally Posted by canis View Post
I thought it was bad practice to top up this usage? Otherwise when you replace the pads, when the piston is forced back to top, all the extra fluid overflows....?
To avoid this, you simply attach a tube to the bleed nipple and open the nipple prior to pushing the piston back in.
As the piston is retracted to accommodate the new pads, this will eject the worst fluid out of the system (the caliper fluid) via the bleed nipple and no overflow will occur at the reservoir.
Best practice though is to refresh all the fluid when replacing the pads to give the best operation and avoid having to revisit the area prematurely.
__________________
2002 S60 SE D5 Manual
209000 miles
cheshired5 is offline   Reply With Quote
The Following User Says Thank You to cheshired5 For This Useful Post:
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 05:51.


Powered by vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.