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" > PV, 120 (Amazon), 1800 General

Notices

PV, 120 (Amazon), 1800 General Forum for the Volvo PV, 120 and 1800 cars

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

Volvo Amazon and PV Brake Drums

Views : 1504

Replies : 14

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old May 8th, 2021, 16:41   #1
Salop Farmer
Member
 

Last Online: Mar 27th, 2024 23:08
Join Date: Feb 2019
Location: Oswestry
Default Volvo Amazon and PV Brake Drums

Having got to a rear axle refurbishment on my 544 restoration I noticed the rear drums were a bit scored. Having discovered how expensive these are to replace I thought I would skim them out on a lathe. Well they cleaned up after machining about 0.020” out of the diameter. There is absolutely no information in any of the Volvo manuals I have regarding the maximum diameter the drum can be (either through wear or machining). But having spoken to Amazon Cars,Rob uses a gauge to check the diameter, which measures 230mm (9.055”). If the gauge goes in the drum he scraps it. I am wondering if machining the drum bore to no more than 9.030”diameter is in order. Does anybody know please?
Salop Farmer is offline   Reply With Quote
Old May 8th, 2021, 18:19   #2
Volvo_133
VOC member
 

Last Online: Mar 27th, 2024 20:16
Join Date: Jan 2008
Location: Sheffield
Default Drums

I have also seen the info regarding the drum maximum diameter being 229mm.My amazon has been idle through I'll health followed by the dreaded covid lockdown. The rear brakes were stripped, cleaned, checked. The drums were both 227 mm diameter. I also have 2 spare drums which are 227mm diameter. I have no official info or diameter detail for new drums, maybe some kind person will tell us the new drum internal diameter. I am hoping mine last a few years more.
Chris
Volvo_133 is offline   Reply With Quote
Old May 8th, 2021, 19:05   #3
Salop Farmer
Member
 

Last Online: Mar 27th, 2024 23:08
Join Date: Feb 2019
Location: Oswestry
Default

According to the official Volvo manual the drums when new are 228.6mm (9”) internal diameter. My query is what is the maximum oversize that is acceptable. Thinking about it the drum starts to wear from day one of the cars life and presuming there is no scoring how did Volvo technicians know when to replace them?
Salop Farmer is offline   Reply With Quote
Old May 8th, 2021, 21:31   #4
Volvo_133
VOC member
 

Last Online: Mar 27th, 2024 20:16
Join Date: Jan 2008
Location: Sheffield
Default Drums

The Volvo mechanics possibly removed the drums, if there was no "step" in them to be ground off, they were re fitted.
Volvo_133 is offline   Reply With Quote
Old May 10th, 2021, 14:07   #5
Derek UK
VOC Member
 
Derek UK's Avatar
 

Last Online: Yesterday 17:01
Join Date: Jul 2006
Location: Chatham
Default

The Green Book says that maximum radial throw allowed is 0.006" (0.15mm). The problem with grinding the drums is that new shoes won't match the radius. Volvo has very specific instructions about grinding the shoes to match the drums. Pre disc brakes that procedure was common but finding someone with facilities to do that now may be difficult. Not doing this may mean that the full surface of the lining may never contact the drum even after many thousands of miles. This is also one of the reasons that the PV brakes are notorious for pulling to one side or the other when braking. Quick hard breaking can have you off the road or or into the opposite lane. Not good!
Rob's rationale, shown I think in one of his videos, is that if you reduce the thickness of the drum, it greatly reduces its ability to dissipate heat. Being rally orientated this is very important but perhaps normal quiet motoring on normal roads would stress them too much.
Green Book -Brake Drum - Check the friction surfaces of the brake drums and radial throw. The radial throw shouldn't exceed 0.15mm (0.006"). If the surface is hollow, scratched or cracked the drum should be replaced. Rust spots or small scratches can, however, be polished or ground off."
Derek UK is offline   Reply With Quote
The Following User Says Thank You to Derek UK For This Useful Post:
Old May 10th, 2021, 15:15   #6
Salop Farmer
Member
 

Last Online: Mar 27th, 2024 23:08
Join Date: Feb 2019
Location: Oswestry
Default

Hi Derek thanks for that detailed reply. I have done the front disc brake conversion to my PV so when I actually get it on the road it will be interesting to see how the brakes perform. Any issues at all will make me bite the bullet and purchase new rear drums. Am also considering fitting a servo into the system. Any body done this on 544 and was it a big plus? Thanks.
Salop Farmer is offline   Reply With Quote
Old May 11th, 2021, 10:01   #7
Underdrive
Senior Member
 

Last Online: Feb 25th, 2024 19:57
Join Date: Jan 2014
Location: stranraer
Default

Something isn't right here, if the official new diameter stated by Volvo is 228.6mm how can V133 have some at 227mm? And for Rob to dismiss them at 230mm would mean bearly 0.5mm thickness of wear, surely Volvo in the 60's would have allowed for more durability than that plus they were notorious for over-engineering. Maybe 228.6mm is actually Volvo's max diameter.
Underdrive is offline   Reply With Quote
Old May 11th, 2021, 14:35   #8
Salop Farmer
Member
 

Last Online: Mar 27th, 2024 23:08
Join Date: Feb 2019
Location: Oswestry
Default

Sorry cannot answer your question.According to the official green Volvo section on brakes the drum diameter when new is 9” which equates to 228.6 mm.I have machined my rear drums to 229.1 to get them to clean up. Will try them out with my front disc conversion and see how it goes.
Salop Farmer is offline   Reply With Quote
Old May 14th, 2021, 17:21   #9
simonvolvo
Member
 

Last Online: Jan 23rd, 2024 08:52
Join Date: Nov 2010
Location: Cape Town
Default

Quote:
Originally Posted by Salop Farmer View Post
I have machined my rear drums to 229.1 ...
You may have over-done it (if only a little).

The direct link to the page I want to refer does not seem to work, but you can get to it by going to the index at:

http://www.networksvolvoniacs.org/in...rie:How_To%27s

and then go to section B and click on:

Bremse. Arbeiten an 1 – 2 und 2 mal 3 Kreisanlagen ..mit entlüften.,

It then takes you to the relevant page. About halfway down the page, for Daten Bremssysteme PV544 (Buckel), it says:

max permitted diameter 229 mm – if it is above that, replace.
simonvolvo is offline   Reply With Quote
The Following User Says Thank You to simonvolvo For This Useful Post:
Old May 14th, 2021, 18:41   #10
arcturus
arcturus
 
arcturus's Avatar
 

Last Online: Yesterday 09:21
Join Date: Mar 2006
Location: Sagres Portugal
Default

Re grinding the profile on the brake shoes, shouldn't they wear to the correct profile fairly quickly?
__________________
life's too short to drink bad wine
arcturus 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 02:22.


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