Brake/Clutch Pedal-Box Rebuild Info

Dr.Jeff

Dr.Jeff

True Classic
The topic of rebuilding the pedal box, including replacing the master cylinders and all other aspects, has been discussed countless times. Currently I'm in the middle of going through two of them at the same time - one from a '79 and the other from a '85 (figured I'd get all of it out of the way at once). Before starting I looked through the forum for write-ups to review. But despite knowing there have been literally hundreds of things posted on it, I had a difficult time finding much. A lot of that is likely due to my "search" skills (or lack of). Also I think many of the discussions were buried within another thread topic or had titles that do not show from common search words. And much of it may have been general comments about how much it is a dreaded task rather than any type of "how to guide". So I thought I would try to bring together as much of the related useful material as possible in a single thread. A general reference point if you will.

The great new "Best Of" feature has this: https://xwebforums.com/forum/index.php?tags/box-pedal-box/
Looking at it you see it needs more added. So if nothing else maybe the references posted here can be added to that?

Even the "X1/9 Wiki" does not have anything for the master cylinders or the pedal box in general. So hopefully something can be added there as well.

Here are some of the threads I found:

https://xwebforums.com/forum/index....and-clutch-master-cylinders.29420/#navigation

https://xwebforums.com/forum/index.php?threads/that-plastic-pedal-box-bearing.25400/#navigation

https://xwebforums.com/forum/index.php?threads/74-pedal-box-project.25800/#navigation

https://xwebforums.com/forum/index.php?threads/74-pedal-box-project-part-2.25869/

https://xwebforums.com/forum/index.php?threads/clutch-pedal-spring-install.25805/

https://xwebforums.com/forum/index.php?threads/pedal-box-and-fluid-reservoirs.32869/

https://xwebforums.com/forum/index.php?threads/brake-fluid-hydraulic-fluid-reservoir-tubing.21848/

https://xwebforums.com/forum/index....-clutch-fluid-reservoir-line-with-what.32023/

https://xwebforums.com/forum/index.php?threads/brake-line-nut-replacements.33258/#navigation

https://xwebforums.com/forum/index.php?threads/pedal-box-and-fluid-reservoirs.32869/

Some of these threads include additional links to more threads. I should have copied them separately, but maybe someone else can add them to the list. I also know I found others but failed to save them, sorry. So please add whatever you can to help build a better reference source. Likewise, if any I linked are not appropriate then please say so and I will delete them (I might have copied some unintentionally).

Another thought. Perhaps one of the gurus on the Factory Workshop Manual knows how to link any useful material from it to this list.
 
I figured I should post this portion separately from the above list of info links, to avoid cluttering it.

While going through my two pedal boxes I've had several thoughts that I'd like to share:

You will be working with brake fluid. That is hazardous to both you and your car. Please use appropriate safety precautions. For you that includes gloves and eye protection. For your car that means covering anything that could possibly be contacted (directly or indirectly) with the fluid.

Frozen hydraulic line fittings (flare nuts). There are several great suggestions in the above listed references how to deal with this. But I observed something I found interesting. The nuts that connect to aluminum components (like the square junction blocks on later models) do not seem to get stuck. They all came free easily on both cars. But the nuts that connect to steel or cast iron (like the clutch master line, or caliper lines) were all very stuck. I finally cut both clutch nuts off the back of the masters after multiple attempts of soaking with penetrating fluid, direct heat, impact, using several types of wrenches and vice grips, etc, etc. Even after cutting them off and putting the master in the bench vice I could not get the nuts to free up. They are permanent. I recall that in all of the previous write ups this same pattern often existed; those cases where the nuts came off easily where the ones into aluminum, while those cases where the nuts were frozen were the ones in steel or cast iron. Hummm. If this pattern is true then maybe having some sort of aluminum adapters to fit between the flare nuts and the non-aluminum components would be useful? Naturally anti-seize is also a good thing.

Access to remove the pedal box. On one of my cars the seats are already out, as is the steering shaft, center console, etc. The other car still had everything in it. Honestly I did not find it much easier with everything removed. On the car with everything still in place, I just pushed the seat all the way back, loosened the steering column and moved it to the side, and leaned in from the doorway to access everything. The car was raised a couple feet off the ground so leaning into the door was not as difficult. I will say that removing the pedal box is the easiest part of the job though. It only took me a couple hours to remove both boxes (I work very slow), but I've spent a couple days after that rebuilding them. And I can see where reinstalling the box will be MUCH more difficult than removing it. So I may rethink the removal of other things then.

Differences between the '79 and '85 pedal boxes. I know some of our members are interested in the little changes that Fiat made over the years. Both of mine are 1500 5-speeds with the "newer" style boxes. But the '85 box is different than the '79. Same layout, same components attached to it, but the actual metal box structure is lighter and designed differently. The '85 has fewer reinforcement structures welded to it. It has a large cut-out in the backbone with "Z" bends in the sides, assumably as a "crash structure". It also has more little locating tabs that go over the hoses (although most of them were never used from day one).

Similarities between the '79 and '85 boxes. The plastic pedal bushing was frozen to the brake pedal on both cars, but the clutch pedals were not (on both). Oddly, with both the brakes felt fine; the pedal moved freely without noises, etc. That is because on both cars the plastic bushing had deformed where the little locking key holds it in place (at the end next to the brake pedal). That allowed the whole bushing to rotate in the box with the brake pedal. That wore grooves into the bushing. I had to use a hydraulic press to remove the bushing from the box/brake pedal on both boxes. And even then it was not easy to get them out. There was a LOT of rust build up inside the brake pedal pivot, despite the bushing being plastic (a bit odd).

I was able to refurbish both of the plastic bushings to reuse them. In the process I decided to purposefully create a little bit of extra clearance between the bushing and the brake pedal pivot. Not enough to cause a lot of slop in the pedal, but enough to allow for a freer movement even if some crud begins to build up again. I'm also wondering if adding a zerk fitting might be a good idea, to allow the occasional addition of more lube? Another thing I did to enable the reuse of the plastic bushings was flip them around, with the clutch and brake pedals now riding in different locations (opposite ends). That gives "new" material for them to act on and eliminated any play from wear of the bushing. To do this I had to cut a slot into the side of the bushing where the retainer key goes. While doing that I decided to add a second key to the opposite side in the hopes of helping prevent the bushing from rotating in the housing (should the brake pedal begin to get a little sticky again).

I'll add more thoughts as things come up. Please feel free to add your own.
 
I think most previous posts had more to do with loosening the flare nuts or how things were routed. As you probably know by now, the actual refurb once the pedal assembly is on the work bench is rather straight forward.
 
carl said:
the actual refurb once the pedal assembly is on the work bench is rather straight forward
Click to expand...
True, but it has also been a lot more work than I imagined. Like most jobs on old cars there have been a host of unexpected issues to contend with.

Regarding getting the pedal box out of the car, here are a couple things I did that seemed to make things much easier:

After sucking out as much of the brake fluid as possible from the reservoirs (I used a "MightyVac"), I cut the three feed lines at the point where they cross over from the scuttle into the firewall. I'm referring to under the plastic 'hump' cover, where they make the bend. That is easy to reach from inside the frunk, where you can place a rug under them to catch any remaining fluid. Then only very short stubs of the hoses remain on the masters and they come out with the whole pedal box, without having to contend with getting the rusted clamps off and yanking the stuck hoses off the nipples while it is all still under the dash. I figure that if I'm replacing both masters, rebuilding the box assembly, and basically redoing the entire system, then it is worth replacing the feed hoses as well. So cutting them is no loss. And in my case I also had to replace the cracked reservoir (going to use three of the small ones and mount them on the driver's side).

While this might seem obvious, it may be worth mentioning. The only flare nuts (hardline fittings) you need to remove while the pedal box is still in the car are the bigger one on the back of the clutch master, and the three smaller ones on the lower sides of the two aluminum junction blocks (either side of the box). Remove these four while the box assembly is still solidly mounted in the car (to hold the box while you wrestle with the fittings). All of the others will come out with the whole assembly and are easier to remove with everything on the bench. This is for the later style (1500) pedal box. Judging by the prior threads, the 1300 boxes are a bit different. By the way, that was another thing I noticed when researching the subject, most of the references are only for the early style box.

Once the pedal box assembly is out of the car, take it somewhere outside where it won't hurt to get brake fluid on the ground and pump both pedals by hand a few times. A lot more fluid will come squirting out of the masters (be sure not to squirt yourself, use eye and hand protection). This helps avoid the fluid from dripping all over everything as you get it to your workbench and tear it down.

I elected to take the whole thing directly to my parts washer first to remove all of the accumulated gunk before touching it further. Old leaking brake fluid combined with 'rust dust', deteriorated rubber compounds, dissolved paint products, dirt, and the liberal amounts of penetrating oil you just soaked everything in, make for a very large mess. Then your photos of how it all goes together are easier to see when you can't remember how to put it back together (actually it is very straight forward). Normally mixing solvents (parts washer) with hydraulic systems is a no no. But in this case everything will be replaced, renewed and rebuilt, so things will be thoroughly cleaned before reassembly.
 
What are you planning to do with the clutch line you had to cut? I used a compression fitting and added about 2 foot length of copper line with the proper bubble flare pre made....worked fine. Didn't have to do that with the Fatrat but did need to use one of those dished copper washers to make the joint tight on the replacement clutch MC.

Makes you really appreciate the cable actuated clutch on the 128.
 
I cut the clutch fitting through the nut right up against the body of the master cylinder. Used a thin rotary cut-off wheel on a air die grinder. That way very little of the hardline was lost. I will place a new nut over it and reflare the end (bubble flare) with the line on the car. It should allow enough length to fit back onto the new cylinder without having to extend the line. Looks like there is a long run of that line back toward the firewall and across to the tunnel, so if needed I can bend it a little here and there to get more length.
 
Here is another question. What would be a good coating for all of the brake components and pedal box to protect them from rust, yet be impervious to brake fluid? In one of those earlier threads Bob Brown stated pretty much all of the typical paints, powder coating, epoxy, and I can't recall what else, will not hold up to brake fluid. At first I was surprised that powder coating won't last, but then it is just a plastic coating.

That was a fairly old thread, so I wonder if the "ceramic" paints were readily available then. The latest engine and brake caliper paints are some sort of ceramic formula. Maybe that is more resistant to brake fluid? Although that could easily be a marketing thing, calling it ceramic. Much like the use of that term for car wax and other products. I'm surprised words like "nano" or "micro" aren't used more with this sort of stuff.

Or what about things like rubberized coatings? Or truck bed coating? I'm not a fan of "POR", but is it any different for this application? Chrome plating would work but that is WAY too expensive for this (but it might look pretty cool). Ideas?
 
Rub them down with WD-40 once a week and move on to something more interesting!
 
carl said:
once a week
Click to expand...
I stopped reading at that point. I don't do anything once a week. :D

I painted everything today using brake caliper paint. The thought was if it is designed for brakes then maybe it will be more resistant to brake fluid leaks. But I really doubt it. I'm sure it is just regular paint charging more for saying "caliper paint".
 
Carl, I rebuilt my pedal box in a way that I thought was correct and there are leaks...
Do you want to come and tell me what I did wrong?...
 
Well, my sister lives in Akron...…..never mind, tell us where yours leak. Supposed to be a sealed system so leaks are not a good thing.
 
carl said:
Supposed to be a sealed system
Click to expand...
So how do you explain all of the leaked brake fluid on every pedal box that has come out? ;)
Kind of like how the engine should not have oil leaks. Eventually they all do, some sooner than others.
 
on the last peddle box repair we did. We found that the supplied hose nipples (for the supply lines) were the wrong size and would seep, (had to totally remove it all again and buy some new fittings as the old ones broke on removal). Maybe this problem is happening here as well?
 
On one of the pedal boxes I removed, one of the old nipples was cracked and leaking. [Don't think about that statement too hard or it will make you sick to your stomach.] :oops:
 
Ive done two pedal box renovations now and neither of them leaked. The only real issue I had was on the 1300 where prior work by a monkey had caused a number of the flares/unions to be rounded off and one that had been overtightened so much it couldn’t be reused and that one did leak. Contrary to Dr Jeff I found the flares into the master cylinders to be more robust than the ones into the aluminium connecting blocks. Maybe due to previous hamfisted work but the threads in the connecting blocks is just not as durable as the master cylinder ones.
 
NEG said:
the threads in the connecting blocks is just not as durable as the master cylinder ones
Click to expand...
Just to be clear, I was not referring to the robustness of the threads, but to the propensity for the nuts to "freeze" into the different metals. All are dissimilar metals relative to the nuts, but in the cases I've noticed (mine as well as several other forum members), the nuts that were in aluminum did not get stuck as much as the nuts in iron or steel. But that isn't scientific, just a casual observation. And as you say, there are lots of variables at play - such as the work of previous parties. So I do not think it is significant...only a bit curious.

Agreed that there should be no leaks after refurbishment of the box. But history tell us it happens, with resultant damage to the paint, leading to rust issues. So I hoped to find a paint (or other coating) that might be more impervious to brake fluid IF a leak or spill should occur.
;)
 
P_20181211_190524.jpgVery nice of you to consolidate all of this great information for others Dr.Jeff. When I did my box rebuild it was starting to leak around the supply hoses from the reservoirs. The ends of the hoses were badly cracked, one of the hose clamps had turned to powder, and the top of the box was starting to rust under one of the hoses where the paint had been eaten away. When I repainted I sanded away the rust, then shot it with rattle can black trim paint. Then I clear coated the whole thing and the new master cylinder castings with DuPont Chroma Clear two stage urethane that was getting elderly. I don't know if it will hold up to Dot3 but it sure is bling!:cool:
 
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I also realized another opportunity for brake fluid to leak onto the pedal box components. If you assemble it and bench bleed the masters, then install the complete unit back under the dash, there is a high likelihood of some brake fluid dripping out while wrestling with it going back in. So even if you do not have any immediate leaking fittings or hoses, there is still the possibility of fluid getting on your new paint job.

And speaking of paint choices, the brake caliper paint I used wasn't that good of an idea. I haven't found out how susceptible it is to brake fluid yet, but I have discovered it chips easily (went on really thin) and does not have a great finish. The label said something about ceramic paint, but the fine print says it is resistant to brake dust. So I bet the "ceramic" aspect is actually referring to ceramic brake pad dust. ;)
 
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