Bad news - my 1.3S failed its MOT yesterday on front brake imbalance! (by 30%). You dont notice it driving except ther is a slight pull to the left (similar to the effect of camber) on moderate braking.
Very odd as I had rebuilt the calipers 5 years ago. It passed with flying colours since then with actually the o/s being the stronger side (marginally). Any way the offending weak caliper (o/s) pushed out all pistons equally so not sure what the problem is (ie no stuck piston). Can also vouch that there is no air in the system.
Anyone had similar situation??
I guess I am looking to rebuild the offending caliper.
Tim
I can only think the the o/s piston seals have swelled up for no good reason and are resisting the hydraulice pressure more than the other caliper, albeit on hard braking this is not apparent.
front brake imbalance - Girling brakes
Re: front brake imbalance - Girling brakes
Could be caused by many things.
If the pistons are a bit sticky, or the pads rusty on the edges thus restricting movement, then of course this could be a contributory factor. But if the pads were in constant contact with the disc because of this, then perhaps the disc has become glazed? 30% imbalance is a lot indeed.
Old Harry Manning was absolutely rigid on pad replacement practice. One was issued with a fine file - a warding file in fact - with which one cleaned the surfaces inside the caliper so that the pads slid in very easily. Excellent policy thta I have followed ever since on any car I have had to work on.
One good way of deglazing discs, though not easy on a Fulvia because of the difficulty in removing them, is to subject the discs to a dose of acid from a battery. they look horrible afterwards but are beautifully deglazed!
Paul
If the pistons are a bit sticky, or the pads rusty on the edges thus restricting movement, then of course this could be a contributory factor. But if the pads were in constant contact with the disc because of this, then perhaps the disc has become glazed? 30% imbalance is a lot indeed.
Old Harry Manning was absolutely rigid on pad replacement practice. One was issued with a fine file - a warding file in fact - with which one cleaned the surfaces inside the caliper so that the pads slid in very easily. Excellent policy thta I have followed ever since on any car I have had to work on.
One good way of deglazing discs, though not easy on a Fulvia because of the difficulty in removing them, is to subject the discs to a dose of acid from a battery. they look horrible afterwards but are beautifully deglazed!
Paul
Re: front brake imbalance - Girling brakes
And a very remote possibility: play on he wheelbearing. Insufficient torque of the ale nut?
-
lancialulu
- Posts: 244
- Joined: 21 Dec 2008, 19:53
Re: front brake imbalance - Girling brakes
Paul
I like Harry always made sure the pads were free and they were very free and not binding at all when I examined them after the test. The disk does not looked any different from the other side and I dont suspect glazing.
Huib
Interesting re wheel bearing at it failed that as well! (Due to sounding "rough" - there was no play but my testers reject anything by sound first then play!!! As it happens I have now had the expeirence of removing a front wheel bearing retainer nut (1.5m extension on 3/4inch bar on tool) which I though I wasnt going to succeed then it let go with such a bang I though I had broken so many parts of the car.... So I fitted a new bearing and did it up real tight (S1 suspension with double nut ), put it all back together and still no difference - ie still feels a slight pull to the left. (What is the torque for the axle nut? - difficult to assess as the tool cannot take a torque wrench - hence I do it up with 1 meter lever and body weight!) - my manual stated the retaining ring but not the axle...
BTW the bearing is interesting as I washed out the old dried up grease and examined all of it for roughness chips etc and couldnt find anything wrong so I have regreased, reassembled, and have it as a spare. Feels just like one out of the packet.
One thing I can think of is the caliper is slightly different from the left side and (I think) from the other 2 fulvias right hand side, in that the upper bleed valve on this one is on the top whereas on the other calipers they are on the side.....
Tim
I like Harry always made sure the pads were free and they were very free and not binding at all when I examined them after the test. The disk does not looked any different from the other side and I dont suspect glazing.
Huib
Interesting re wheel bearing at it failed that as well! (Due to sounding "rough" - there was no play but my testers reject anything by sound first then play!!! As it happens I have now had the expeirence of removing a front wheel bearing retainer nut (1.5m extension on 3/4inch bar on tool) which I though I wasnt going to succeed then it let go with such a bang I though I had broken so many parts of the car.... So I fitted a new bearing and did it up real tight (S1 suspension with double nut ), put it all back together and still no difference - ie still feels a slight pull to the left. (What is the torque for the axle nut? - difficult to assess as the tool cannot take a torque wrench - hence I do it up with 1 meter lever and body weight!) - my manual stated the retaining ring but not the axle...
BTW the bearing is interesting as I washed out the old dried up grease and examined all of it for roughness chips etc and couldnt find anything wrong so I have regreased, reassembled, and have it as a spare. Feels just like one out of the packet.
One thing I can think of is the caliper is slightly different from the left side and (I think) from the other 2 fulvias right hand side, in that the upper bleed valve on this one is on the top whereas on the other calipers they are on the side.....
Tim
Re: front brake imbalance - Girling brakes
The torque for both the retaining ring and the inner axle nut is 30kgm. Before mounting the wheel bearing everything has to be thoroughly cleaned from dirt and rust. Any play on the bearing may result in wobbling discs which reduces the breaking efficiency.
-
lancialulu
- Posts: 244
- Joined: 21 Dec 2008, 19:53
Re: front brake imbalance - Girling brakes
On page ast6671 in the Fulvia Technical Manual(which I found after reading Huib's last post) it says 20kgm for the front wheel bearing locking and 20kgm for the rear bearing inner - but dated 1962 when it was updated from a Flavia spec. Has it been updated since??
Tim
Tim
Re: front brake imbalance - Girling brakes
See Technical Databook Fulvia 08/0010
30 for the front
20 for the rear
I consider those minimum values.
30 for the front
20 for the rear
I consider those minimum values.
Re: front brake imbalance - Girling brakes
Yes, I remember a customer with a 1600 who complained that his brake pedal position varied; he said that sometimes it was near the floor and sometimes fine.
Of course it was near the floor after he had been round a right hand bend. yes the hub nut was loose.
He was lucky; I tightened it and there was no slack or roughness and proper brakes too. SO I would say that a slack bearing would inevitable lead to a long brake pedal.
Of course it was near the floor after he had been round a right hand bend. yes the hub nut was loose.
He was lucky; I tightened it and there was no slack or roughness and proper brakes too. SO I would say that a slack bearing would inevitable lead to a long brake pedal.
Re: front brake imbalance - Girling brakes
Old Harry used to say that "They must be FT" - he meant er, very tight."
I can still see him now, with a 3/4" drive sliding tee bar with like you, a 3ft piece of tube added. He would then lean on it until he became slightly purple!
I can still see him now, with a 3/4" drive sliding tee bar with like you, a 3ft piece of tube added. He would then lean on it until he became slightly purple!
-
lancialulu
- Posts: 244
- Joined: 21 Dec 2008, 19:53
Re: front brake imbalance - Girling brakes
Paul
I have a photocopy of some torque settings for the fulvia translated into ftlbs. For the bearing retaining ring nut it quotes something like 214ftlb or as Harry M would say a F*****g long bar and all your weight! I cannot remember where I got it but it was in my early days of Fulvia ownership maybe 30 years ago when someone gave me a photocopy of the red concise repair manual!! Doing the math this is about 30kgm.....
Tim
PS I checked that the lines are not crossed over - they are not, the hoses were changed for new 6 years ago and are fine, and both calipers exercise the same. No wheel bearings were loose and no disk is in a poor state and the pads were new a few years ago and have done little mileage. I will out of sheer frustration rebuild the caliper with new seals and put some oem girling pads in (I got a few new ones from an ebay deal a couple of years ago).
I have a photocopy of some torque settings for the fulvia translated into ftlbs. For the bearing retaining ring nut it quotes something like 214ftlb or as Harry M would say a F*****g long bar and all your weight! I cannot remember where I got it but it was in my early days of Fulvia ownership maybe 30 years ago when someone gave me a photocopy of the red concise repair manual!! Doing the math this is about 30kgm.....
Tim
PS I checked that the lines are not crossed over - they are not, the hoses were changed for new 6 years ago and are fine, and both calipers exercise the same. No wheel bearings were loose and no disk is in a poor state and the pads were new a few years ago and have done little mileage. I will out of sheer frustration rebuild the caliper with new seals and put some oem girling pads in (I got a few new ones from an ebay deal a couple of years ago).