front brake imbalance - Girling brakes

[Huib]

I mentioned the wheel bearing out of experience. Some years ago I worked on a poorly braking Fulvia. I did check the play on the wheel bearings and found none. I changed pads, calipers, discs, masterbrake cilinder, flex hoses. Everything. Did not change anything. For some reason I retorqued the axle nut, It transformed the car. Braked like throwing an anchor.

I used the word wobbling above. It is perhaps the wrong word. It would cause as Paul say the pedal to go deeper as the pads are pushed back. A better picture may be high frequency oscillating.

Thinking a bit more about it, it may be that I did change both front wheel bearings and not just retorque the axle nuts.

Was the bad wheel bearing on the side which braked well or braked poorly?

[lancialulu]

It was on the poor side. I have no problem with viable or poor pedal travel or rock solid hard braking. I have run the car some 20-40 kms since putting ing the new bearing so will check (again) tightness - I have seen in the past these bearings need a lttle tweak after a bit of use.... The new bearing feels very solid without any "wobble"...

I am advised the test is at 5mph (8kph) so not very conclusive at that speed. On observing both calipers without pads being exercised by the brake pedal (with care so no piston popped out) the poor side was beautifully extended on all 4 pistons whereas the left side was not. This proves to my mind that the hydraulic pressure is getting to both sides reasonable the same....

Tim

[VAR1016]

Your mention of Harry reminded me that on one of my coupés ("Beeza" I think) a rear caliper quite by itself began to stick - I should add that this car was as the ads say "in daily use"

I spent a long time freeing it off. It was fine for about a week and then began to stick again. in those days no need to worry: I went to Harry's took a caliper off one of the scrappers, paid the usual fiver and all was well - until a very stupid woman drove into the back of poor old Beeza and wrote her off. I wasn't even moving at the time and the woman said to me "what about my radiator?" her husband dragged her away as I obviously did not see the joke!

It is quite possible that rebuilding may be the only solution, though from what you say there doesn't appear to be a sticking problem. One thing: the original pistons are chromium-plated and I have seen examples where the chrome has started to peel off. At Evolution Engineering, Barry once bought some austenitic stainless steel bar stock and we turned up some pistons. We couldn't sell a single one.

Funny that.

Paul

[lancialulu]

Paul

You may be right about the rebuild option and I have some new seals ready to get messy!

I remember these pistons were in excellent shape as opposed to others in my other cars where the chrome has slightly pitted on the most exposed end of the piston - obviously I threw out any poor ones on thos calipers selecting from spares (now no spares left!). I remember Jai Sharma had some stainless pistons on ebay a couple of years ago and they went for more more than I could justify. If you have a source of stainless pistons I could be interested in at least two sets.

I suspect if i put it back together now it would pass - but become annoying/fail again just like your caliper.

Hey ho

Tim

PS do you drive a Fulvia in France (or still own your experimental injected blue one?)

[VAR1016]

lancialulu Wrote:
-------------------------------------------------------
> Paul
>
> You may be right about the rebuild option and I
> have some new seals ready to get messy!
>
> I remember these pistons were in excellent shape
> as opposed to others in my other cars where the
> chrome has slightly pitted on the most exposed end
> of the piston - obviously I threw out any poor
> ones on thos calipers selecting from spares (now
> no spares left!). I remember Jai Sharma had some
> stainless pistons on ebay a couple of years ago
> and they went for more more than I could justify.
> If you have a source of stainless pistons I could
> be interested in at least two sets.
>
> I suspect if i put it back together now it would
> pass - but become annoying/fail again just like
> your caliper.
>
> Hey ho
>
> Tim
>
> PS do you drive a Fulvia in France (or still own
> your experimental injected blue one?)


Sorry, no SS pistons at the moment.

I still have the Fulvia (I repainted it Amaranto Montebello) you can see a snap on the bottom of the page of my blog. I do not run it at present (poverty!) Also it would be extraordinarily difficult to register it in France, since the French have a system almost as stupid as that in Italy. In England I could put an aero-engine in the Fulvia, get an MoT and away I'd go. Here if it is not homologé or in Italy omologato one is setting oneself up for a long and expensive battle with ll the power of the République or Republicca!

[lancialulu]

Epilogue

After much testing of open clipers on both sides I could not see any difference in "static" hydraulic pressure.

So I cleaned both disks and put new Girling OEM pads in and took it for a test run.

It still pulled slightly to the left and had a tendancy to lock the left wheel.

Back at my garage I had no option to rebuild the offending rhs caliper.

This I did and took for a test run - now no sign of pulling to the left - indeed on an emergency stop (a pedestrian wanted to examine the lancia badge on the front of my car just to be sure it was a Lancia!) it pulled up dead straight.

So back to the MOT test station.

Tester said what had I done to the front wheel bearing? I said I had replaced with new one with difficulty and great cost.
I asked why he asked that. He said that the other side was now a bit noisey!!! (I gues he was hinting that he would fail that side next year if I didnt replace that bearing with great difficulty and cost.

On the brake test it seemed to go OK.

On asking if it passed he said yes but only just??? What??? Well now it appears that the righ side is now the stronger and imbalance was 23% (fail at 25% apparently).

So I have a ticket to ride for another year with another caliper to rebuild and a new wheel bearing to sort.

The only thing I could see "wrong" with the old caliper is the seals seamed softer than than the new ones leading me to think that the soft seals act as a brake on the piston under pressure.

Moral of this story is to do both sides not just the "offending" one.

PS Having dismantled a 40 year old bearing on a car that spends most of its time standing around waiting to be used, and where the grease is all dry and horrible, I doubt the theory that bearings fail due a ball bearing denting a race. It may be on small bearings on other cars but on Lancias these are so big!!! Anyway I saw no damage and after a thorough clean and reassembly it is like a new bearing. - I may just reuse that one on the left hand side....

Tim

[Huib]

Most bearings fail as a result of improper mounting which includes under torquing.

And of course when the grease has become soap after 30+ years.

There is of course also the statistical failure rate which applies to any ball bearing.

These are double row angular contact ball bearings designed to take high axial as well as high radial loads. The inner races should ideally be one single unit. However it would then not be possible to put in the relatively high number of balls. The reason for the high torque is to make sure the two inner races behave as one single unit.

[Bart Verbeek]

Tim

My local 'brake parts shop' -specialized in yep: brake parts rebuilds old Dunlup and girling brakes for the local Jaguar dealership & Belgian Jagclub.
I'm not sure any more about the pricing and finshing (austentic steel or rechroming or or or).

I pressume, Jags also run on your Isle? Perhaps your local brake parts shop - or the UK Jag club can provide an adress?

I wasn't that interested, my brakes were ok and my zagato's were done by Huib some years ago...

glad the problem is solved on the brakes!

gr

Bart

[lancialulu]

Hiya Bart

Hows the september Bart./Huib show coming on.

I still need to rebuild the other side....

But interestingly when I had rebuilt the Z1600 brakes the first time some 3 years ago the tester said he had never seen such a perfect BALANCE to the brakes.... They seem to have kept their balance since then... Same with the 1600HF... Seems odd that this other car with exactly the same brakes / silicon brake fluids/ seals etc should fail. I hope this does not point to a 6 year cycle.

Any one got a view of silicone brake fluid ...... Interestingly I found some surface rust forming inside the pistons which I thought silicon was not hydroscopic....

Tim

[racing]

to use a silicone brake fluid is a typical mistake.( my opinion )

as you wrote it is not hydroscopic so you have separted the oil and water. The result is
rust.
It destroy particulary the 1. Series brakes. Also as wrote the 2 Serie.

It make sence for race cars. There you change typically continous the fluid.
And you have much higher temperature.

Andreas