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" > 850 / S70 & V70 '96-'99 / C70 '97-'05 General

Notices

850 / S70 & V70 '96-'99 / C70 '97-'05 General Forum for the 850 and P80-platform 70-series models

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

Noise and pulsing

Views : 1171

Replies : 23

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old Dec 11th, 2019, 18:31   #1
Dippydog
Premier Member
 

Last Online: Mar 24th, 2024 19:47
Join Date: Jun 2016
Location: S****horpe
Default Noise and pulsing

Agreed to do a couple of tip runs for granddaughter today.First run went smoothly,returned to hers and loaded up for second run.On setting off again the first 4 applications of the brakes brought a "grinding" noise[but not like worn out pads on discs]wasn't constant-more as though something was catching a a given point as the wheels rotated.At the same time I could just feel a "pulsing" through the car and a definite pulsing of the brake pedal.After the first 4 applications the noise and the pulsing ceased and all was back to normal again.On setting back off from the tip the same thing happened again,but this time only for the first 2 applications of the brake after which it cleared again but this time the ABS light lit up and stayed on!! Looks like being Saturday before I'll have chance to get underneath to see if I can spot the problem,so in the meantime has anyone any ideas/thoughts on the issue?
Car is a P1 V70 2.4 n/a manual. TIA.
Dippydog is offline   Reply With Quote
Old Dec 11th, 2019, 18:32   #2
Dippydog
Premier Member
 

Last Online: Mar 24th, 2024 19:47
Join Date: Jun 2016
Location: S****horpe
Default

Sorry forgot to mention it sounds to be coming from N/S front.
Dippydog is offline   Reply With Quote
Old Dec 11th, 2019, 19:19   #3
SteveSarre
Premier Member
 

Last Online: Mar 27th, 2024 09:57
Join Date: Oct 2004
Location: London/West Country
Default

Hello Dippydog

Maybe you are hearing the ABS kicking in? It sounds like a buzz.

You could rule it out by unplugging the power cable to the ABS module (between the battery and firewall).

I dont have a picture to hand, but the cable has about 4 wires and goes to half way down the front side of the ABS module and pump unit.

If it is kicking in when it doesn't need to, most likely is a faulty ABS wheel sensor. Also possible but slightly less likely is a faulty ABS module. Is the speedo behaving normally?

What year is your car?

I guess you don't have a code reader?

HTH
Steve
__________________
V70 2.5 Turbo AWD Man. 1999 Red
V70 2.5 10V Auto 1998 Green
C70 T 20V Auto Conv. 2001 Blue, C70 T5 Auto Conv. 2000 Blue
V70 2.5 Turbo AWD Auto 1998 Green, V70 2.5 10V Auto BiFuel 1999 Red (scrapped) V70 20v Auto 1999 Green (scrapped)
SteveSarre is offline   Reply With Quote
Old Dec 11th, 2019, 19:32   #4
SteveSarre
Premier Member
 

Last Online: Mar 27th, 2024 09:57
Join Date: Oct 2004
Location: London/West Country
Default

PS

This video from Robert DIY shows the two connectors to the ABS module

https://www.youtube.com/watch?v=0zV8nGeGukQ

Go to 3:24

For diagnosis, you don't need to undo the big connector, just remove the power connector and abs will no longer kick in.

Obviously the car wont have ABS protection while this is unplugged so do so at your own risk (and avoid skids or harsh braking).

I don't think there is a fuse that you can remove to achieve the same objective (but check your users manual/electrical diagrams).

Steve
__________________
V70 2.5 Turbo AWD Man. 1999 Red
V70 2.5 10V Auto 1998 Green
C70 T 20V Auto Conv. 2001 Blue, C70 T5 Auto Conv. 2000 Blue
V70 2.5 Turbo AWD Auto 1998 Green, V70 2.5 10V Auto BiFuel 1999 Red (scrapped) V70 20v Auto 1999 Green (scrapped)
SteveSarre is offline   Reply With Quote
Old Dec 11th, 2019, 20:55   #5
Dippydog
Premier Member
 

Last Online: Mar 24th, 2024 19:47
Join Date: Jun 2016
Location: S****horpe
Default

Thanks for your replies. The car was first registered 1st January 2000 I've never heard the ABS kick in on any car I've had with it fitted as I've not needed to brake hard enough to operate it,so I don't know what it sounds like.The noise definitely sounds to be coming from N/S front-is that where ABS unit is?No I don't have any form of code reading equipment.
Dippydog is offline   Reply With Quote
Old Dec 11th, 2019, 21:00   #6
Dippydog
Premier Member
 

Last Online: Mar 24th, 2024 19:47
Join Date: Jun 2016
Location: S****horpe
Default

Sorry just re-read your first reply,my battery is directly behind the N/S headlight and in front of the air filter box[effectively sandwiched between the two].
Dippydog is offline   Reply With Quote
Old Dec 11th, 2019, 21:40   #7
Dippydog
Premier Member
 

Last Online: Mar 24th, 2024 19:47
Join Date: Jun 2016
Location: S****horpe
Default

Sorry yet again! Yes the speedometer was working as normal at all times
Dippydog is offline   Reply With Quote
Old Dec 11th, 2019, 23:36   #8
Luxobarge
Premier Member
 

Last Online: Today 08:49
Join Date: Jan 2011
Location: Horne (Nr. Horley)
Default

Classic symptoms of a corroded or cracked reluctor ring. Have a really good look at both rings at the front, if they're dodgy then replace them. They're cheap and apparently not too difficult to change, although I've not done it myself.
__________________
Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.
Luxobarge is offline   Reply With Quote
Old Dec 12th, 2019, 08:08   #9
Dippydog
Premier Member
 

Last Online: Mar 24th, 2024 19:47
Join Date: Jun 2016
Location: S****horpe
Default

Oddly enough although I've never suffered such a failure before so I don't know the symptoms my first thought was the reluctor ring.I believe they're reasonably priced-I'll have to look that up-and just in case that's my problem I'll consult the bible according to St Haynes as to replacement procedure.
Dippydog is offline   Reply With Quote
Old Dec 12th, 2019, 08:56   #10
huron
Master Member
 

Last Online: Dec 19th, 2020 17:24
Join Date: Apr 2009
Location: Bodmin
Default

Try https://www.jandrcvjoints.co.uk/
I've used them and very good.
__________________
huron
2009 V70 2.4 geartronic in red.
huron is offline   Reply With Quote
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 09:52.


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