Soft Brake Pedal - Fiat
Discussion
I am trying to sort out the brakes on my old Fiat Punto. they pull the car up but theres not much bite when you first get on the pedal so it feels like you have to apply more effort. they dont inspire confidence when pressing on. I have driven other cars similar year and same model with a much more responsive pedal.
everything is new on the system (discs, pads, master, rubber lines, calipers, sliders, handbrake cables, compensator valves etc) the servo booster is original though. the vacuum hose has been inspected and the one way valve checked OK. engine off I get a firm pedal and it sinks about an inch or 2 once the engine is started.
the bleed nipples on all calipers are facing upwards. clear fluid is coming through all 4 corners yet that squishy pedal is still there. when driving the pedal doesnt improve if you pump it whether on the move or stood still suggesting that there are no internal leaks. there are certainly no external leaks. I think the master is still fine.
The pedal cannot be "adjusted" to lean a bit more onto the master pushrod. the servo has an adjustment inside for the pushrod but its never been touched and I dont want to start now for fear of binding the brakes on if over adjusted.
The ABS is original and has not been touched but do not suspect a problem with it and there no ABS light. ABS kicks in when provoked.
all parts are wearing true and evenly. no binding anywhere. no pulling to one side either.
the master cylinder was not fitted by me and I am wondering if the garage failed to bleed it before installation as the mounting is angled upwards. so brand new out of the box could there be a constant tapped bubble of air at the front of the master bore ? Its a pain to remove the master to bench bleed it but really I am running out of ideas as to what else it could possible be thats giving me this soft pedal.
my only other idea was to buy a set of brake line clamps and go around clamping each line off one at a time then trying the pedal to try and isolate any one problem circuit which I guess is the easier option before pointing to an air bubble in the master. .
everything is new on the system (discs, pads, master, rubber lines, calipers, sliders, handbrake cables, compensator valves etc) the servo booster is original though. the vacuum hose has been inspected and the one way valve checked OK. engine off I get a firm pedal and it sinks about an inch or 2 once the engine is started.
the bleed nipples on all calipers are facing upwards. clear fluid is coming through all 4 corners yet that squishy pedal is still there. when driving the pedal doesnt improve if you pump it whether on the move or stood still suggesting that there are no internal leaks. there are certainly no external leaks. I think the master is still fine.
The pedal cannot be "adjusted" to lean a bit more onto the master pushrod. the servo has an adjustment inside for the pushrod but its never been touched and I dont want to start now for fear of binding the brakes on if over adjusted.
The ABS is original and has not been touched but do not suspect a problem with it and there no ABS light. ABS kicks in when provoked.
all parts are wearing true and evenly. no binding anywhere. no pulling to one side either.
the master cylinder was not fitted by me and I am wondering if the garage failed to bleed it before installation as the mounting is angled upwards. so brand new out of the box could there be a constant tapped bubble of air at the front of the master bore ? Its a pain to remove the master to bench bleed it but really I am running out of ideas as to what else it could possible be thats giving me this soft pedal.
my only other idea was to buy a set of brake line clamps and go around clamping each line off one at a time then trying the pedal to try and isolate any one problem circuit which I guess is the easier option before pointing to an air bubble in the master. .
Edited by ToothbrushMan on Thursday 4th October 10:45
Is the brake pedal actually soft compared to others you have driven or are you just having to press it harder because the brakes don't have the same bite?
What pads are fitted?
I fitted some cheap 'Mintex' pads from eBay to a Mondeo once and it was as if they were made of wood. I fit OEM pads now, too many experiences with disappointing aftermarket pads, even genuine ones from reputable brands.
What pads are fitted?
I fitted some cheap 'Mintex' pads from eBay to a Mondeo once and it was as if they were made of wood. I fit OEM pads now, too many experiences with disappointing aftermarket pads, even genuine ones from reputable brands.
HustleRussell said:
Is the brake pedal actually soft compared to others you have driven or are you just having to press it harder because the brakes don't have the same bite?
What pads are fitted?
I fitted some cheap 'Mintex' pads from eBay to a Mondeo once and it was as if they were made of wood. I fit OEM pads now, too many experiences with disappointing aftermarket pads, even genuine ones from reputable brands.
no bite. hard to say if the pedal is soft or if i just need to push harder.. im sure ive had a firmer pedal with bite higher up before.What pads are fitted?
I fitted some cheap 'Mintex' pads from eBay to a Mondeo once and it was as if they were made of wood. I fit OEM pads now, too many experiences with disappointing aftermarket pads, even genuine ones from reputable brands.
also its like the car is easier to lean on its nose more when braking yet the front suspension is all new too so its the brakes that are not behaving somewhere......in those cars where the bite is immediate you never got that nosed diving effect because they were grabbing efficiently.
ive been searching online for suggestions too and its a minefield of possibles......
ive looked at my master cylinder and the outlet port at the front of it is right at the very front of the casting so very little area beyond that port where you can have a trapped air bubble at the front of the bore.
ToothbrushMan said:
in those cars where the bite is immediate you never got that nosed diving effect because they were grabbing efficiently.
That makes zero sense.Maybe you're simply braking harder in the car now you're used to it, which is why you're seeing more pedal travel and more dive.
ToothbrushMan said:
I am trying to sort out the brakes on my old Fiat Punto. they pull the car up but theres not much bite when you first get on the pedal so it feels like you have to apply more effort. they dont inspire confidence when pressing on. I have driven other cars similar year and same model with a much more responsive pedal.
everything is new on the system (discs, pads, master, rubber lines, calipers, sliders, handbrake cables, compensator valves etc) the servo booster is original though. the vacuum hose has been inspected and the one way valve checked OK. engine off I get a firm pedal and it sinks about an inch or 2 once the engine is started.
the bleed nipples on all calipers are facing upwards. clear fluid is coming through all 4 corners yet that squishy pedal is still there. when driving the pedal doesnt improve if you pump it whether on the move or stood still suggesting that there are no internal leaks. there are certainly no external leaks. I think the master is still fine.
The pedal cannot be "adjusted" to lean a bit more onto the master pushrod. the servo has an adjustment inside for the pushrod but its never been touched and I dont want to start now for fear of binding the brakes on if over adjusted.
The ABS is original and has not been touched but do not suspect a problem with it and there no ABS light. ABS kicks in when provoked.
all parts are wearing true and evenly. no binding anywhere. no pulling to one side either.
the master cylinder was not fitted by me and I am wondering if the garage failed to bleed it before installation as the mounting is angled upwards. so brand new out of the box could there be a constant tapped bubble of air at the front of the master bore ? Its a pain to remove the master to bench bleed it but really I am running out of ideas as to what else it could possible be thats giving me this soft pedal.
my only other idea was to buy a set of brake line clamps and go around clamping each line off one at a time then trying the pedal to try and isolate any one problem circuit which I guess is the easier option before pointing to an air bubble in the master. .
Is it lack of bite or more a case of the pedal simply travelling before biting? If drums at the back are they automatically adjusting? Also, how's the handbrake? Sometimes tightening up the handbrake effects the brake pedal travel.everything is new on the system (discs, pads, master, rubber lines, calipers, sliders, handbrake cables, compensator valves etc) the servo booster is original though. the vacuum hose has been inspected and the one way valve checked OK. engine off I get a firm pedal and it sinks about an inch or 2 once the engine is started.
the bleed nipples on all calipers are facing upwards. clear fluid is coming through all 4 corners yet that squishy pedal is still there. when driving the pedal doesnt improve if you pump it whether on the move or stood still suggesting that there are no internal leaks. there are certainly no external leaks. I think the master is still fine.
The pedal cannot be "adjusted" to lean a bit more onto the master pushrod. the servo has an adjustment inside for the pushrod but its never been touched and I dont want to start now for fear of binding the brakes on if over adjusted.
The ABS is original and has not been touched but do not suspect a problem with it and there no ABS light. ABS kicks in when provoked.
all parts are wearing true and evenly. no binding anywhere. no pulling to one side either.
the master cylinder was not fitted by me and I am wondering if the garage failed to bleed it before installation as the mounting is angled upwards. so brand new out of the box could there be a constant tapped bubble of air at the front of the master bore ? Its a pain to remove the master to bench bleed it but really I am running out of ideas as to what else it could possible be thats giving me this soft pedal.
my only other idea was to buy a set of brake line clamps and go around clamping each line off one at a time then trying the pedal to try and isolate any one problem circuit which I guess is the easier option before pointing to an air bubble in the master. .
Edited by ToothbrushMan on Thursday 4th October 10:45
As a fulltime mechanic Ive often done a full brake overhaul on a car, and although the brakes work fine they dont feel as good as they did originally but after a few hundred miles bedding in they come back to normal. If this vehicle has the Fiat system of friction automatic adjusters on the rear drums it is always difficult to get a good feeling pedal straight away after brake overhaul.
i have noticed that the drivers side rear brake disc is not being swept fully by the new pad. the inboard surface is getting a full sweep and the passenger side is fine.
I did some googling and I think that as far this issue goes I have perhaps got either a rogue out of true disc on that side or rogue outboard pad thats not entirely flat but will in time eventually wear itself to the disc and sweep over that slightly rusty none swept area.
be interesting to see how the pedal beds down. all the brake system is new and ive probably done around 200 miles so far.
as pads bed in does the pedal drop slightly or stay the same but just have a better feel.
I did some googling and I think that as far this issue goes I have perhaps got either a rogue out of true disc on that side or rogue outboard pad thats not entirely flat but will in time eventually wear itself to the disc and sweep over that slightly rusty none swept area.
be interesting to see how the pedal beds down. all the brake system is new and ive probably done around 200 miles so far.
as pads bed in does the pedal drop slightly or stay the same but just have a better feel.
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