GT brake caliper pistons Jaguar Part no from IBS Brake Parts.. 64325438 1D13A7. need to be machined down, will take the genuine caliper kits from Isuzu.

The originals are chromed. Machining would take off the chrome so these replacements are apparently not chromed?

The pictures coming up with a search of the part number do not show a center pin. The Honda expert rebuilding the smaller Sumitomo calipers swears that breaking the pin out renders the caliper unusable.

Beyond the issue of the pin keeping the piston centered, on the opposing end of the piston, the side facing the brake pad, there is a T shape cross section that matches a horse shoe shaped clip on the back of the brake pad. This clip attaches the brake pad firmly to the brake piston to reduce brake shoe drag when the brake disengages.

This might be "substitutable", but does not meet the definition of "interchangeable".

Ahh Shit, I will have to throw them in the bin then

Going back to the original post, this requires the use of a lathe, and it's "interchangeable"?

Why not start out with: "Buy a piece of 4140 alloy 2 1/2 inch round, and turn the outside diameter down to 2.17 inches, turn down a groove for the outer seal, cup (bore) the inside, then part the piece at the appropriate height".

The level of work and tool requirement involved is just about exactly the same.

At what point is any of this "interchangeable"?

From the looks of the rest of the entries, the "Parts Interchangeability" sections looks more like cross references parts and part numbers that match dimensions and can be directly substituted without the use of a lathe.

I think it's a valid point.

I don't know too much, but there are plenty of pistons that stay centred by the seal against the caliper bore, and the pad is spread the few microns from the disc by the slight warp present in all discs. The Galant discs on the Florian are like this & it works fine. Maybe not perfect, but neither am I !

Cheers, Matt.

It's not a question of what can be made to work (temporarily, permanently, or anywhere in between).

The section is about interchangeable parts. That implies they fit without serious modification or machine work. It also implies that the piece could be disassembled and reassembled with the original parts, and it would not have been modified to the point that the originals no longer fit.

The description starts out with:
"need to be machined down"
Maybe every home in Australia comes with a garage that happens to be equipped with a metal cutting lathe. But I seriously doubt it.

The second step is not stated, but involves breaking the center guide pin out of the caliper. It can't be removed without damaging it, and it can't be reattached.
The only expert on these calipers (Datsun guy, not Honda, my mistake earlier):
http://www.datsunparts.com/Brakes
Says the guide pin is important enough that if it is broken, the caliper is not rebuildable.
They through it was important enough to include it to begin with. They used it on the smaller Fairlady calipers. People are saying they need to restore their cars to OEM spec for historic racing, then this is part of the OEM spec...

(I seriously do not understand a country that bans drum-to-disc conversions because they have two bolts to hold the caliper instead of four, or an aluminum bracket to hold an aluminum caliper, but they have no problem with people hogging out the inside of a brake caliper to make non-standard parts fit...)

I have to say that unless someone is going to stand up and state "So-and-so is going to make machined calipers available and supply them on an ongoing basis", then this does not belong under the heading of interchangeable. it belongs under the heading of a rather involved customizing project to make something that does not originally fit, fit.

This would be the same as saying that a 4 foot by 8 foot sheet of steel is interchangeable with a front fender/wing. Step one is to walk over to your hundred ton press and insert the sheet between the two stamping dies. Step two is to press the button to smash the dies together. Step three is to trim the edges. But does everyone have a hundred ton press and a set of stamping dies?

Maybe jt if you are going to play on words then the moderators should change the heading The calipers were sent to a brake shop and they used these parts to repair them This info was shared with other forum members that may need the info. Pr95 and myself have been involved with a number of rebuilds and even though these rebuilds are not to the standard of some we are prepared to share what we learn as we go to assist others and other info from forum members have helped us.
I can only imagine if you are going to build the perfect gt that every thing is 100%. I will be keen to observe this rebuild and take some tips. I know you have contacts in Japan and I have visited recently for the purpose of research and contacts and I am happy to suggest that the Japanese are struggling to produce the perfect car also.
As for the legal side it was done by a professional business and as our government cant get much right they choose to follow the US and people are happy to take legal action. So in the event that these calipers are the cause of a accident it would be become the responsibility of the professionals that rebuilt them.
My next rebuild I will use genuine parts only and if I cant get the I will get them reproduced to genuine spec and it can sit in the shed for the next 40 years while it happens. I think I will have second thoughts myself sharing knowledge public.
Another fact is the people restoring belletts do not have a lazy $70000 to rebuild these cars to the standard you are suggesting This being the case will leave even more cars in sheds slowly decaying as it is often pointed out here that the cars are worthless. I have spent almost half of the above amount on three of my rebuilds over the years and current market value in Australia is $15000.[based on ebay sales] I can say if I was to sell a gt I would not sell it in Australia I would propose to sell it back to its homeland as they can get twice that for a car of a lesser quality of my dodgy examples. With all due respect the Japanese examples I observed were not to the quality of our higher quality examples here in Australia in saying this I am not only talking about rebuilt cars.
Based on the facts of above these cars would have no future they have to be built with what is available or we wait for jt to produce all the parts to original specs.

JT191 I READ YOUR POSTING AND AM EXCITED AS MOST OF US IN AUSTRALIA ARE WITH YOUR KNOWLEDGE YOU IMPOUND ON US .....HOWEVER FOR SO MANY YEARS WE HAVE READ YOUR IMFO AND NOT ONCE DOES A PICTURE APPEAR TO SHOW US HOW TO BUILD A WONDERFUL CAR MOST THE GUYS HERE SHOW EACH OTHER OF THE ACHIEVEMENTS... BUT ..FOR YOU NOTHING ???? DO YOU ACTUALLY HAVE AN ISUZU ?? I REST MY CASE .DAVO

I posted this information as it might help someone with a similar problem, not to cause argument and the bullshit that goes with it. Take it or leave it, I couldn't give a rats arse if you use it not, but I have a car that I can drive on Australian roads legally. In future I will keep any mods to myself.

Geoff

To all you guys that bought caliper repair kits from Glenn, you now have twice as many, as I kit does the car not a wheel.
BONUS. I also want to thanks Glenn for helping me out with this project, that is what this group is about Mateship.
Cheers Geoff

Don't be discouraged Geoff ol' mate, I'm grateful for any tips.

My old '67 Crown S has the caliper centre pins, with a ratchety edge to keep the pads close to the disc. I remember them being a pain to get to let the pistons retract to fit new pads. The good thing is the original pads did 200,000 miles, so I only had to do the job one time!

I don't see how it would matter that the pins were removed. But I'm not any expert.

As for 'interchangeability' versus 'interchangeable with modification', I'm probably a bit too lazy to worry about the difference, and I've got a hubcap to polish.

JT, you just about got a bite outa Davo, and hes one of the easygoingest happynaturedest blokes I know, so............buggerme! (Not really, I wouldn't like that)

Cheers, Matt.

Very pleased to help Geoff. And thanks for the tip that the kits do both calipers !

On the question of changing the pistons to Jag type, I have no idea if there will be any issues or not but i think the brake experts know what they are doing. From what I can tell, the brake place down here does exactly the same thing, with GT caliper re-builds for club members. A quote from them recently was over $500 the set for full re-build. They looked like brand new.

One doesn't always need to have a lathe etc for some jobs if the Pro's have the facilities and do it for you. The same place machined all my other brake parts (slave cyl and master) and s/s sleeved them

In the past I organised a group rebuild of the GT pistons for the BCCV. Cleaned up original pistons and then hard chromed and re-machined. Unfortunately after we got a batch done, the guy sadly passed away. And I have had no luck finding anybody interested in doing the same job on a small number of pistons. So the only option is to fit the Jag bits, it seems to me. Engineering a whole new 'legal' brake set-up instead is a whole new exercise in this country.

glenn

I have used another company to do mine they machine the old ones down and rechrome them.

You may be right here in Vic too. I talked to the guy at BGT here about doing my calipers last year. I don't recall exactly what they do but its quite possible they do the same. re-build the pistons also. Others in the BCCV use BGT and may have had some done and could comment on it.

Nothing that has been stated here changes the fact that the Jaguar brake caliper piston is not interchangeable with the Dunlop/Sumitomo brake caliper piston, as supplied and without modification.
In fact, the installation requires rather serious and extensive modification to both the piston, and the caliper.
I have to renew my objection to this thread being included in the interchangeable section, and that it be moved to the brake section.

If Dave and Geoff or others want to huff-and-puff and act hurt because someone pointed this out, then so be it.

Regarding the numerous comments:

I have spent a small fortune having replicas of the original brake pieces reproduced, out of the morbidly curious desire to find out if the original brakes, in good working order, are either as-good-as, or as-bad-as, everyone says, or if the reputation is mostly due to the fact that people are assigning opinions to 40+ year old, unmaintained brakes.
After replacing everything else, I arrived at four damaged pistons, in need of replacement. I inquired with all my sources, and found none available in Japan. Several serious issues prevent me from attempting to reproduce the piston: The piston is chrome plated, but the material and coating are both soft enough that the spring mechanism is installed in the back and staked into place with chisel _after_ the chrome plating is applied. I’d wager the past rechroming efforts were done without removing the spring mechanism, and ignored the moving pieces which are not chromed and should be removed while the chroming is done to prevent them from being stuck together.
This, combined with the lack of several other rather important pieces, brought me to the realization that there will be no concourse restoration of this vehicle, it will have to be a resto-mod if it is to ever see the pavement again. I’ll be using a nice set of Wilwood Powerlite calipers, which are just as “interchangeable” as the Jaguar pistons, they’re new, they have a larger brake pad, and it’s cheaper to throw them away and buy a new set, than it is to rebuild them. When I get bored with them, I’ll throw away all the OEM reproduction parts and put less expensive vented disc brakes on all four corners with Dynapros on the front, smaller Powerlites on the back, and a JTU069(B) power assist brake master cylinder.
I’ve already decided that I’m a carburetor atheist, and one of the spare 4XE1 engines will end up under the hood.

Sorry I haven’t made much progress lately. That economic recovery three summers ago never arrived here. I’ve been spending the majority of time exchanging goods and services that I do not enjoy doing and making, for money. As the goods and services that I do enjoy doing and making, which are apparently in demand only by me.

A person of “professional” status may imply, but in no way guarantees any qualification, expertise, certification, or competence at the thing they are being paid to do. Just because you pay someone to cram brake caliper pistons into a hole they were not designed to go into, does not mean that the job has been done with any level of proficiency. It simply means that someone was paid to do the job, and nothing more. “Professional” just means that someone does the job for a living, not that they do the job well. There are just as many examples of big name Australian companies who sell complete garbage products, as there are examples of every other nationality. Australia has no exclusivity to perfection or junk. How about those Whiteline Gemini sway bar end links that are nothing more than two shock-hour-glass-eyelets jammed into a figure-8 chain repair link?

As for living in the land of litigation, the full understanding of being sued for everything you have, has the side effect of streamlining a lot of bureaucracy. Our safety inspections are done at service stations and repair shops. Each tech is expected to do 48+ inspections in an eight hour shift. At ten minutes per inspection, that leaves about four minutes to look at the car, four minutes to fill out the paperwork, and two minutes to put money in the till and make polite conversation with the customer. In the four minutes allotted to look at the car, the important points are to make sure the wiper blades are not worn out, make sure all the lights work, make sure the horn works, and make sure there isn’t a hole in the muffler. They recently added that the car must go up onto a lift and be looked at underneath. The lift goes up and down quickly. They give a quick shake a wheel to check bearings and balljoints, and shine a flashlight on a rotor and pad to see if they look thick enough. And if they have any questions about any of the odd cars that I own, they ask me if that’s the way it is supposed to be, because no one else knows anything about the cars.
For any car over 25 years of age, the owner can apply for antique plates, which means the car is safety inspected once, and never again. It is assumed that any car licensed under antique status is kept so well that any additional inspections would be a waste of time.
And our friends in the state of Florida published a study proving that there is no difference in the rates of mechanical related accidents or injuries in states that have motor vehicle safety inspections, and in states which do not have motor vehicle inspections. So they, and several other states, completely did away with all safety inspections altogether.

I have requested that this tread gets moved to the brakes section .
As for road worthy we have the same here some states do it others don't. Australia has laws for each state so what may be legal in 1 state may change over the boarder.
The best thing you yanks can do for road safety is stop driving on the wrong side of the road .

!!!!!!


Moved, per GT Orf's request.

Are we all happy?

Not the least bit interested in what this "WANKER" has to say, just a waffler of opinion, I see you fancy brake pipes on Ebay, My whole job cost me less than your pipes, all for a car that will do less than a 1000ks ayear. DICK HEAD.

Many Thanks PR95, I have not laughed like that for ages, I and many many others call them "septic tanks" for that very reason, Cheers PR95 an keep up with the great Resto work. Cheers Steve

sounds like a job for...
The Irritator!