Another 504 question
- Thread starter Trent172
- Start date
I had my 1974 504 converted. I don't think it was that difficult or expensive
pipe threads are different so you really need a donor car for them and f and r calipers and compensator valve changed from parralel holed to ofset for mounting
Of your going to do that may as well put a late 504 booster with a 505 3port master cylinder, did that to my cousins 504 and feels good. And 505 ones are much cheaper than 504 ones, you'll need to source a late booster aswell. 505 doesn't fit unless you modify the inner guard.
Then you can use the calipers off the back of a 505 they are the same as late 504.
A single master has a great pedal feel than the twin 504 late master, then 505s are better again. Saying that dad's rally car and 504 v8 are single master and it's never failed, so of it isn't broken or giving trouble leave it?
Cheers BP
Then you can use the calipers off the back of a 505 they are the same as late 504.
A single master has a great pedal feel than the twin 504 late master, then 505s are better again. Saying that dad's rally car and 504 v8 are single master and it's never failed, so of it isn't broken or giving trouble leave it?
Cheers BP
rarely happens
Long as new front and rear brake hoses and be ok,
Dual masters are metric thread and double flared unions
Lines need to be changed
I have done this when putting 604 brakes on a 504
Lines need to be changed
I have done this when putting 604 brakes on a 504
Have a read of this thread for what's involved
Brake line materials, manufacturing, flaring, hydrovacs & handy tools. Edited & some new material
Some of this may possibly have been raised before ~ but this is meant as a refresher: Beware 10mm x 1mm & 3/8" x 24TPI flare nut threads are similar looking & sometimes seem to fit, but 3/8" thread in metric will be loose & the 10mm won't go in the 3/8". NEVER SUBSTITUTE ONE FOR THE OTHER. 1...
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Total brake failures do happen but they are rare in a well maintained system. Like the equally rare tyre blow out they are memorable for the driver. I had three separate brake pipe failures in an old 403 wagon, two in city traffic, but in those days they didn't worry me too much and I just continued on to my destination.
The 504 brake system was considered by Girling to be the best of any car on the Australian market and testified as such before a Parliamentary Enquiry into Australian vehicle safety in 1974.
The 504 brake system was considered by Girling to be the best of any car on the Australian market and testified as such before a Parliamentary Enquiry into Australian vehicle safety in 1974.
How interesting Russell! What year did 504's go dual circuit?
I had a single circuit master fail in a back street in suburbia, but I had just been going down a road with various traffic lights (which I would have had to stop at) that had trucks thundering down it. I considered myself very, very lucky.
Since Peujohn has had his converted, perhaps you should grill him for info ? My knowledge is theoretical, but I do know for a fact that the later master cylinder sits at a different angle on the booster, so you'd need a late model booster and master, plus you'd have to mount the booster through different holes in the firewall.
You could change over the whole system or make a different coupling where all the lines are joined together at the bottom of the engine bay (mounted on the cross member, I think). So above that would be concave flare metal pipes and below that would be the older style convex flare.
Complete conversion would be better (though more expensive) as you can then use 505 rear calipers, which will always be more readily available secondhand in the future.
New compensation valves are hard to find (though not impossible) but I think Ianrobbo probably still has a few he re-sleeved in stainless. And it's good to replace this valve....even if doesn't leak, it seizes up and thereby affects the rear braking. I probably had an accident once because of this....it will cause one rear brake (left) to lock up when you stomp on the brakes.........which is really when you want it all to work.
Whatever you plan to do, here's my most important advice : if your single circuit brakes ever feel different at the pedal, that is a sign of imminent catastrophic failure. I felt mine go different and bought a kit (seals) which I kept in the car. I neglected to see that any failure would be total and catastrophic. Oh well....at least when they did fail that time, I was able to get home by changing the seals in ten minutes. But that was only a temporary fix to get home....I got a new cylinder after that.
Since Peujohn has had his converted, perhaps you should grill him for info ? My knowledge is theoretical, but I do know for a fact that the later master cylinder sits at a different angle on the booster, so you'd need a late model booster and master, plus you'd have to mount the booster through different holes in the firewall.
You could change over the whole system or make a different coupling where all the lines are joined together at the bottom of the engine bay (mounted on the cross member, I think). So above that would be concave flare metal pipes and below that would be the older style convex flare.
Complete conversion would be better (though more expensive) as you can then use 505 rear calipers, which will always be more readily available secondhand in the future.
New compensation valves are hard to find (though not impossible) but I think Ianrobbo probably still has a few he re-sleeved in stainless. And it's good to replace this valve....even if doesn't leak, it seizes up and thereby affects the rear braking. I probably had an accident once because of this....it will cause one rear brake (left) to lock up when you stomp on the brakes.........which is really when you want it all to work.
Whatever you plan to do, here's my most important advice : if your single circuit brakes ever feel different at the pedal, that is a sign of imminent catastrophic failure. I felt mine go different and bought a kit (seals) which I kept in the car. I neglected to see that any failure would be total and catastrophic. Oh well....at least when they did fail that time, I was able to get home by changing the seals in ten minutes. But that was only a temporary fix to get home....I got a new cylinder after that.
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Yes I have had this done, many brake shops now make hoses on the spot provided you have samples of the end fittings, you need to be careful with the threads because the metric and imperial look similar. About $30 per hose for my application of putting late 505 callipers on 404 plumbing in a 203. Look for a thread by 'Ringer' in the technical forum to explain the thread differences.
Will do thanks oddfire!
AMENDMENT
When I said : "You could change over the whole system or make a different coupling where all the lines are joined together at the bottom of the engine bay (mounted on the cross member, I think). So above that would be concave flare metal pipes and below that would be the older style convex flare".
I should have said that you will need to create a completely different joiner for these lines. The "IN" side on your existing one will not have enough inlet holes. It will have one only.
And a later model joiner will have two, but the wrong flare. Not sure how you will get around this, but it has been done.
The easiest, fastest and cheapest way is to simply buy a new or re-sleeved (in stainless) master cylinder,. They are about the same price but the re-sleeved one will be superior and easier to get. Plenty of re-sleeving companies around....just give em your old one. And if I made you worried about the compensation valve, Ianrobbo here has re-sleeved ones. They are actually difficult to re-sleeve and most companies won't do them.
Otherwise, find a 505 and change over everything. This will be a pain, and you won't know the condition of the seals in anything unless you change them all, which is time-consuming and expensive.
When I said : "You could change over the whole system or make a different coupling where all the lines are joined together at the bottom of the engine bay (mounted on the cross member, I think). So above that would be concave flare metal pipes and below that would be the older style convex flare".
I should have said that you will need to create a completely different joiner for these lines. The "IN" side on your existing one will not have enough inlet holes. It will have one only.
And a later model joiner will have two, but the wrong flare. Not sure how you will get around this, but it has been done.
The easiest, fastest and cheapest way is to simply buy a new or re-sleeved (in stainless) master cylinder,. They are about the same price but the re-sleeved one will be superior and easier to get. Plenty of re-sleeving companies around....just give em your old one. And if I made you worried about the compensation valve, Ianrobbo here has re-sleeved ones. They are actually difficult to re-sleeve and most companies won't do them.
Otherwise, find a 505 and change over everything. This will be a pain, and you won't know the condition of the seals in anything unless you change them all, which is time-consuming and expensive.