Register Login
Save up to 15% with Adrian Flux insurance!
Reply
 
Thread Tools
Old 23-06-2007   #1
Join Date: Jun 2006
Posts: 1,349
Thanks: 27
Trader Rating: 0
fenton_jd has donated!
United Kingdom 
Braking by itself?!

This has happend quite a few times now....


If I'm breaking down to come up to a junction, I will brake a bit, and then select a lower gear (whilst still braking) and when i engage this slower gear i can physically feel the brake pedal going down?!

Would this have anything to do with clutch/brake fluid?
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

fenton_jd is offline Reply With Quote Quote 
Old 23-06-2007   #2
Misseys Stalker!
Join Date: Nov 2006
Location: at home
Posts: 2,161
Thanks: 43
Trader Rating: 0
vtec has donated!
Re: Braking by itself?!

the calipers are prone to seizing in puntos, if you jack it up and try to turn the wheels by hand you'll know if its one or both of the brakes that are siezed., then you'll need to replace with a new/used caliper.,
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

vtec is offline Reply With Quote Quote 
Old 23-06-2007   #3
Join Date: Apr 2007
Location: Yep, still here.
Posts: 2,861
Thanks: 330
Trader Rating: 0
United Kingdom 
Re: Braking by itself?!

Brake servo's operate on a vacuum basis to aid pressing the pedal. The vacuum is drawn off the inlet manifold and fills a chamber, when the pedal is pressed the vacuum is "used up" in increasing the pedal effort (a test of servo efficiency is running the engine, switch off, pump the pedal to destroy the vacuum until it stiffens-up, hold pressure on the pedal, now start-up. The pedal should sink as the vacuum builds.)

I wonder if you're braking enough to use up the vacuum, then when you drop a gear the increased engine revs create an extra "bit" of vacuum which causes the pedal to drop slightly further. Diesels do this a lot due to using engine-driven vacuum pumps.

Either that or you've got a slight brake fluid leak, though I'd expect you to notice it whilst stationary and just holding pressure on the pedal (it would sink if fluid was leaking).

__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

D4nny8oy is offline Reply With Quote Quote 
Old 23-06-2007   #4
Join Date: Jun 2006
Posts: 1,349
Thanks: 27
Trader Rating: 0
fenton_jd has donated!
United Kingdom 
Re: Braking by itself?!

ahh thanks for that danny boy^^

That seems to make perfect sense about why it is happening.

My brakes are also pretty crap, so a change of caliber will be needed.

Was just worried about the pedal dropping
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

fenton_jd is offline Reply With Quote Quote 
Old 24-06-2007   #5
Join Date: Apr 2007
Location: Yep, still here.
Posts: 2,861
Thanks: 330
Trader Rating: 0
United Kingdom 
Re: Braking by itself?!

Sticking brakes aren't necessarily a stuck caliper.

Usually one pad sticks due to a build-up of brake dust/ corrosion. I'd take the pads out and clean-up the contact surfaces in the carrier and lubricate with copper-grease first before condemning a whole caliper.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

D4nny8oy is offline Reply With Quote Quote 
Old 25-06-2007   #6
Bravo 1.8 HLX FTW
 
The Sultan's Avatar
Join Date: Jul 2006
Posts: 3,851
Thanks: 298
Trader Rating: 0
The Sultan has donated!
United Kingdom 
Re: Braking by itself?!

my pedal drops a little bit as the engine revs increase

but if yours is very noticeably dropping then maybe there is air in your brake lines making it drop more as air is compressible

maybe all you need is your brakes bleeding
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

The Sultan is offline Reply With Quote Quote 
Reply
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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
Similar Threads
Thread Thread Starter Forum Replies Last Post
(T) Braking problems.. again nomatter Cinquecento / Seicento 4 22-11-2006 15:44
(T) Engine stops when braking (engine temp = normal) MarcSluiter Barchetta 4 07-09-2006 00:52
(T) Engine Cuts out when braking!! mrkippax Bravo / Brava 2 22-01-2006 19:48
(G) GT braking system Luke Punto (Mk1) 1 02-10-2005 23:59