Uno Turbo Front Caliper Install

Your pretty handy with a lathe and milling machine Tony, so why not turn up some thin stainless steel sleeves to fit over the outside of your 34mm pistons, (you could even machine the 34 piston down a little on the OD) so you end up with the Fiat/Bendix original adjuster innards but the piston would be 38mm OD? No need to make the pistons from scratch... and you could do all that while still driving your X19 around until your ready to do the swap over.

The washer that the bearing race runs against looks like muck metal in the aftermarket caliper... the OE ones are very hard chrome steel.

SteveC
 
From the photos, it looks like the ID is about the same for the 34 mm and the 38 mm pistons. Perhaps the OEM internals from the 34 mm pistons would fit in the 38 mm ones?
 
ng_randolph said:
From the photos, it looks like the ID is about the same for the 34 mm and the 38 mm pistons. Perhaps the OEM internals from the 34 mm pistons would fit in the 38 mm ones?
Click to expand...

Perhaps all the hardware besides the pistons could be utilized -obviously those are different :D I wish I hadn't sent my stock ones to MWB as cores now - from the overall look of things the mechanism and associated hardware are all sub-standard in comparison with stock (manufactured to) Fiat component spec.
 
In the OEM 34/38 pistons the internals are all the same parts, and fully interchange.... but the circlip in the aftermarket pistons looks to be a very different section, so for a start the OE round section circlip probably wont fit in the groove...plus Tony still has the issue with the poor steel quality choice for the rear pistons in the aftermarket items...sleeving the originally 34 pistons would give him a solution.

SteveC
 
fiatfactory said:
In the OEM 34/38 pistons the internals are all the same parts, and fully interchange.... but the circlip in the aftermarket pistons looks to be a very different section, so for a start the OE round section circlip probably wont fit in the groove...plus Tony still has the issue with the poor steel quality choice for the rear pistons in the aftermarket items...sleeving the originally 34 pistons would give him a solution.

SteveC
Click to expand...


Everyone on this thread, a big thank you for ideas and innovation to produce a solution.

The internals for the self adjusters are the same in theory. It is the Quality Control that is lacking. The body of the casting and the E brake mechanism are all fine. The caliper pistons are inferior along with the self adjuster mechanism. The self adjuster appears to be interchangeable.

Solutions. The stock Fiat caliper pistons are chrome plated although sleeving is an answer it also requires welding the sleeve to the 34MM piston. Cannot have leak here. Chrome plating and TIG welding are not a winning combination. At the weld zone the chrome will need to be machined off or the weld will be contaminated which now spells failure. The solution would be to press fit a sleeve over the 34MM piston and prior to this operation machine off the chrome finish back to the base metal in the weld zone, then TIG weld the sleeve and do a final machining to size ( 38MM) and polish. Unfortunately I did not measure the piston diameter when I had the caliper apart. I am unsure if the bore is 38MM or the piston is 38MM with the bore being 38MM+ .001" or more. I would have to pull the seal and push out the piston a bit to take an accurate measurement. The whole process in the end will require removal of the calipers from the car to do the refit.

Just a mention here, as I tried to decrease the lash measurement further I purchased a section of .024" stainless steel sheet and made new shim. Sadly it would not allow the caliper to go on to the pads so I had to retract the piston 1/2 a turn, install the new shim and pump the brake pedal, which again left .023" slack, at this time I installed the .020" shim on top of the other and I am good for a few miles.

Last night I took the car out and drove 25 miles. With the slack adjusted out of the rear brake calipers the brake pedal is firmer and has a bottom to it. Travel is a bit longer but then there is a strong resistance and braking currently is equal to the old X1/9 braking system. I suspect that once I get the bugs ironed out the rear adjusters ( and I will post the entire procedure) and the brakes get bedded in braking will be enhanced.

Knowing what we now know now it may be possible to heckle the vendor and get him to drop his price a bit or possibly improve on his product. We won't know until someone give it a shot, it is always worth a try.

Thanks again.

TonyK.

Grimsby Ontario Canada.
 
I messaged FiatInc (the vendor I used to get mine) & outlined the issues/flaws with the product. I bought mine too long ago to get any sort of adjustment/satisfaction. Hopefully they will try to address the production flaws.
 
I have the calipers. But need to know what break hoses i need. How long, which thread, banjo or straight? Anyone?
Thanks.
 
Mxgrds said:
I have the calipers. But need to know what break hoses i need. How long, which thread, banjo or straight? Anyone?
Thanks.
Click to expand...
Are you thinking of the Uno Turbo front calipers (orignial topic of the thread) or the Fiat 125 rear calipers?
 
ng_randolph said:
Are you thinking of the Uno Turbo front calipers (orignial topic of the thread) or the Fiat 125 rear calipers?
Click to expand...

Sorry. Front calipers. I noticed the uno caliper is wider. The hose connection comes very close to the inner fender when wheel points inside. The original x1.9 hose ends in an awkward bend.
 
Uno Turbo calipers are wider and have a different hose inlet location than stock calipers.

Goodridge brake hoses for the exxe. The banjo fittings on the front need to be oriented to clear the body-inner fender and routed to have adequate hose radius over wheel travel and steering form lock to lock. The stock banjo fitting retainer bracket cannot be used to achieve proper service loop with the Goodridge hoses and Uno Turbo front calipers.

There is a not so good image of where the hose ended up. Keep in mind full wheel droop is not the same as running wheel height and steering from lock to lock.

https://xwebforums.com/forum/index.php?threads/uno-turbo-front-caliper-install.31249/#post-262428


Bernice

Mxgrds said:
Nobody?
Click to expand...
Mxgrds said:
Sorry. Front calipers. I noticed the uno caliper is wider. The hose connection comes very close to the inner fender when wheel points inside. The original x1.9 hose ends in an awkward bend.
Click to expand...
 
TonyK said:
As close as I think I can get. It is apparent that the rear brake pads are not adjusted to the disk. A gap of .023" on each side presents it's self with the hand brake off. View attachment 2280

See pictures and thanks for the help.

TonyK.

Grimsby Ontario Canada.
Click to expand...

Finally got to measure the freeplay / lash in my rear calipers - I have .014"

8B2F28A0-9A5E-43EE-9034-C90481C2D70A_zpssuimnlqv.jpg


My brake pedal feels pretty normal at this point, no unnerving drop over the 460 mile trip to Carlisle & back this past weekend. Not sure if I will mess with alterations to the calipers.
 
While at Bob Martin's last week we were kicking the idea of installing a power brake booster. Electric came to mind but the 1990 Cadillac unit is no longer being made and is considered unreliable. Looking at this vacuum unit possibly it would fit in the place of the windshield washer reservoir. Although I have upgraded the brakes I would like more stopping power.

http://www.ebay.co.uk/itm/Medium-Du...315683&hash=item41b78b4048:g:XHsAAOSwXeJYJaeX

Or possibly 2 remote single units can be mounted in the same location again using the stock master as a pilot for the brake booster.

We also looked at the Wilwood master cylinders and 7/8" to 1" can be purchased as well.

Opinions?

TonyK.

Grimsby Ontario Canada.
 
Wow that is a big mother...jeez Louise.

Well it wouldn’t reduce the complexity of the car that is for sure. So you would have the current master cylinder to trigger the two cylinders on this one. Then the line running to the rear from the one and a splitter for the front.

What calipers would you run with this? Likely need a rear pressure reduction valve?

As another somewhat insane choice, could you adapt the ABS system from the Abarth given that the computers want the abs signal anyway?

So in your minds changing to a larger set of more modern rear calipers won’t suffice for increasing the braking of the car?
 
Dan Sarandrea (Phila) said:
I have been able to acquire the caliper brackets but so far no dice on the calipers themselves or the discs.
Click to expand...
Dan hi we can buy the calipers as the MK2 is the same caliper different bracket and disks new over here in the UK it is the brackets we cannot get hold of if you are willing to spend the cash i could buy some for you and post them over to you all obviously at your cost sometimes cheaper calipers and discs come up on ebay every now and then let me know what you would like to do sent a full set to Canada earlier this year
Dave
 
Well done good mod and very well shown I did do the same but have now gonethe extra mile and fitted Punto GT front calipers not had a chance to road test yet as the car is off the road
 
kmead said:
Wow that is a big mother...jeez Louise.

Well it wouldn’t reduce the complexity of the car that is for sure. So you would have the current master cylinder to trigger the two cylinders on this one. Then the line running to the rear from the one and a splitter for the front.

What calipers would you run with this? Likely need a rear pressure reduction valve?

As another somewhat insane choice, could you adapt the ABS system from the Abarth given that the computers want the abs signal anyway?

So in your minds changing to a larger set of more modern rear calipers won’t suffice for increasing the braking of the car?
Click to expand...


I have Uno Turbo front calipers and the 38MM rears. Just the pedal feels a bit soft and braking force is now higher. Braking is better but not lock the wheel up throw you through the windshield better braking.

I will agree about the insane part. First off in my build the wheel sensors are all on the front axles that way no power is limited to the rear wheels by the engine or by wheel slip seen by a over speed situation.

The Abarth uses a 12" vacuum brake booster, where in the hell will that go in the car. Lastly the ABS system is controlled by 12 solenoids in the brake module block and separate brake lines are required to each caliper. Not going to happen.

There are some small 6" remote brake booster that would take up less room and provide 1:1.9 advantage over what I currently have. That is what I am exploring.

TonyK.

Grimsby Ontario Canada.
 
TonyK said:
I have Uno Turbo front calipers and the 38MM rears. Just the pedal feels a bit soft and braking force is now higher. Braking is better but not lock the wheel up throw you through the windshield better braking.

I will agree about the insane part. First off in my build the wheel sensors are all on the front axles that way no power is limited to the rear wheels by the engine or by wheel slip seen by a over speed situation.

The Abarth uses a 12" vacuum brake booster, where in the hell will that go in the car. Lastly the ABS system is controlled by 12 solenoids in the brake module block and separate brake lines are required to each caliper. Not going to happen.

There are some small 6" remote brake booster that would take up less room and provide 1:1.9 advantage over what I currently have. That is what I am exploring.

TonyK.

Grimsby Ontario Canada.
Click to expand...

The smaller booster sounds like a much better solution, likely the right amount of boost. I assumed the ABS idea was just that insane :) Just another idle thought.

As an aside, I found out that the 500L uses a 38mm sliding pin caliper, perhaps this would be a worthwhile mate to the the Uno Turbo front calipers and may be a somewhat better solution than the old caliper design.

Karl
 
kmead said:
The smaller booster sounds like a much better solution, likely the right amount of boost. I assumed the ABS idea was just that insane :) Just another idle thought.

As an aside, I found out that the 500L uses a 38mm sliding pin caliper, perhaps this would be a worthwhile mate to the the Uno Turbo front calipers and may be a somewhat better solution than the old caliper design.

Karl
Click to expand...
Currently I have 38 MM rears from a Scorpion but the lash adjustment in the self adjusters is .026" and a lot of brake pedal is lost filling the caliper to move the piston. For now I have pad shims to take up the excess travel. I am hoping Bernice will chime in and give me her thoughts about any of this.

TonyK.

Grimsby Ontario Canada.
 
TonyK said:
While at Bob Martin's last week we were kicking the idea of installing a power brake booster. Electric came to mind but the 1990 Cadillac unit is no longer being made and is considered unreliable. Looking at this vacuum unit possibly it would fit in the place of the windshield washer reservoir. Although I have upgraded the brakes I would like more stopping power.

http://www.ebay.co.uk/itm/Medium-Du...315683&hash=item41b78b4048:g:XHsAAOSwXeJYJaeX

Or possibly 2 remote single units can be mounted in the same location again using the stock master as a pilot for the brake booster.

We also looked at the Wilwood master cylinders and 7/8" to 1" can be purchased as well.

Opinions?

TonyK.

Grimsby Ontario Canada.
Click to expand...

I like the booster idea. I agree completely that adding bigger brakes all around was a vast improvement over stock, but it needs more oomph. Power assist makes sense to me, vs. farting around with revised masters. At the very least, I would try power assist first. I'll have to research this also for a DTR project, after all, gotta have problems to solve or what's the point? :D

EDIT: hhmmm.... just looked at that booster (that's quite a beast!), so rerouting the brake circuit is obviously required, however that approach seems easier to accomplish than reworking the pedal box, etc., for a revised setup using the stock MC location.
 
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