Abarth 850TC (Fiat 600D) Brake Diagnostic & Shifter Fix

Well, look at this cute little thing

It's an Abarth 850 TC. So these are actually based on the Fiat 600, but Abarth, of course, tuned these things up for racing

And they were the hot ticket for small displacement back in the day. But I'll save the history lesson for another day

We got some issues with this one. We were taking this thing out on a test drive to see if we could identify some clunking in the rear

and all of a sudden it shifted into third and stayed there. The shifter was just a loose wiggle stick

I pulled up this little inspection plate right here and couldn't see it. see any problems with the shifter up here so we knew it was in the back

Fortunately whenever I got under the car I could see the problem right away

This is your shift shaft right here and this is a little coupler and that's the shaft going

into the transmission right there. The bolt that attaches the coupler to the transmission shaft had fallen out

Now fortunately the bolt on this side of the coupler up here was still in

I was able to remove that and hopefully you can see it has a kind of a funny taper shape

to it, I had to get a new bolt and replicate that taper because it screws into the coupler

and this taper goes into a pocket on the shaft here. So let's get this put back together and see

if my new bolt works. All right, we have a shifter again. Now I'm going to locktight those bolts

so they don't fall out again. Just medium string locktide is going to be sufficient. You don't want to

overkill it. So we got the shifter fix, but now we have a problem of a squidgy break pedal

And it's kind of doing something very strange where if you pump it rapidly, you actually lose brake pressure

And normally, you know, you're pump up solid. But yeah, it's kind of weird that when you pump it rapidly, it loses pressure

And if you push and hold, it kind of loses a little bit of pressure

Makes me think there's a leak somewhere, but it's kind of interesting. I've been looking. Can't find one

So on these cars, they have a rear brake drum. And normally, 600s have a front drum too

But check out these cute little discs. Aberth put front disc brakes on it

And also this caliper is kind of interesting. It's got a single piston in the back and two pistons in the front

Now this rotor, I think, has kind of seen better days. You see little chips out of the side of it

And also it kind of seems to be warped as well because he spin it around and drags And unfortunately the one on the other side is dragging like that too But yeah it funny Just look how thin it is tiny

Oh, and also notice how it bolts on. It actually bolts on to the backside of the hub here

Pretty interesting. Now, this car has had some recent breakwork done. You can see brand new rubber hose up here on the front

And I think they also rebuilt these calipers. If we swing around underneath the car, you can see the brakemaster cylinder right here

It's got two hard lines that go to the front brakes and then the single one that runs in this tray all the way to the back and there's a little proportioning valve that sends it to the two rear drums

But yeah, check for leaks all around the master cylinder and looking for leaks all along these hard lines

Can't find any. It's also kind of neat to see just how the pedal arrangement works down here

You have your little return springs for your pedals underneath the car instead of inside and you have your cables for your

accelerator and your clutch going down this tray all the way to the back. This right here is going to be your

brake pedal and you know I can actuate it with my hand somewhat. I would expect that to be

stiffer and not actually be able to do that by hand but I don't know. I think I'm going to call an expert

and see if that's normal. And taking a look at where the rod goes into the master cylinder

I don't see any leaks there either. And I don't know how old this master cylinder is. It could be

that the seals inside of it are shot and it's leaking inside and that could be a possibility

You know, just leaking past its own pistons. You can see the rotor over here isn't really even any better shape than the one on the driver's side

has all these little nicks and stuff in it. The surface of the rotors actually look okay, but yeah, they're definitely warped

How they're stick and drag like that. At the back to the driver side, you can see where the hard line comes out of the tray coming from the front

goes up into this little valve right here. I call it a proportioning valve, but it's probably just a little three-way valve

It's got some sort of little electrical connection on it. And then from there you have a hard line that goes over to the other wheel

and then one that comes over here, and you have a short rubber hose right here

which these look kind of old, they're not new like the front ones are

And then the rubber hose goes over to a hard line that inside the trailing arm and then over to the drum Now I need to get these drums off because the previous mechanics were actually saying that one of these drums isn fitting right

They both seem nice and tight, just sitting on the car like this. They were actually thinking that the clunky noise was coming from the brake drums

They said one of them was loose, but it seems tight to me

The one on the other side does too. But I'm going to take them off and see if I see it

anything obvious. Alright so check it out. Here's how the brake drums go together

They're held on by a bolt and this little wheel locator pin

And of course you have a nice thick aluminum spacer because race car

And then you have the brake drum itself, which is supposed to fit nice and snug up against

the hub and not supposed to be any wiggle at all on this guy, right

This one's actually pretty snug on there. Let's go take a look at the other one

So when I took this one off, the first thing I noticed. was there's this plastic ring on there

I don't think that's supposed to be on there. I'll ask my expert if what he thinks of that

But yeah, that don't seem right. But then let's put the drum on. And check that out

Even pressing it in, so it's on there nice and firmly. And I don't know, but I think that does kind of sound a bit like

their noise that we were hearing. But the thing that doesn't really make sense

to me is I don't understand how that would be even making that noise, even if it is a little

loose like that. Because not only is it sandwiched in with the spacer and these bolts, but the wheel

bolts hold it in too. In fact, let me just throw it back together real quick and we'll see

Yeah, I mean, even though it's loose when it's not bolted in, when it's bolted in, it doesn't

move at all. Not convinced that's the culprit of the noise, but I do think that we should probably

go ahead and replace these drums. Also just noticed, I don't think these are the original studs that the wheels go on

because it looks like this has kind of been fabricated here. The flanched part of it is just a nut

I don't know, maybe it was tack-welded and ground. I think I throw some lock on there and run it back up to where it belongs to right there Hopefully that hold it Another thing I wanted to show you is I think the hubcaps on this thing are just super cool It got this little bar that goes over and a stud on it and this is the hubcap It looks like a knockoff style It actually threads on Just like that

Isn't that cool? You know another one of the things that makes these cars really unique is the front

mounted radiator and I found a very interesting modification. to this one. So it's got coolant pipes that go all the way back to the engine back and back

Well, this one has a very high-tech plastic spacer to keep the coolant hoses from rubbing on the frame here

So yeah, after talking to the expert, he agreed we should replace the brake master cylinder and also those brake drums

Fortunately, the brake drums are standard 600 parts and I believe the master cylinder is too. I'm going to have to look that up and make sure

So I think we'll be able to find those parts no problem. The rotors on the front are special ABARTH parts, so I don't know

We're going to have to find those somewhere. Or it could be one of those cases where they're not really that bad

as long as it's not causing vibrations in the steering, you know

as the rotors are going to flump, flump, flomp, flump. Maybe it's not anything to deal with

And while going over the car, I found a couple other little tiny little problems

Probably not anything you actually want to work on. The steering box is leaking

I mean, they probably just leak. I don't know. Probably not that big of a deal. Just something to keep an eye on

Maybe top it off, like, once a year or something like that. And it kind of looks like the transmission seal where the shift actuation shaft goes in is kind of leaking

Again, is that something that really needs to be done? Probably not

But stay tuned for the brake master cylinder on this guy as well as the drums

Oh, and you know what really has me good? geeking out about this car is that, yeah, I know by the time these cars were being built

he probably had a whole team of people working with them, and he might not have actually

worked on the cars himself. But there's a chance that Carlo Abarth actually worked on this

car himself. And, you know, I mean, I'm sorry, but being a fiat nut, I'm just geeking out over

that. That's so cool. Well, bye. Thanks for watching. See you guys next time