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Big Brakes

n xntrx volvo said:
is there a spare tire that will fit over these? riding with my buddy in his stang w/r 13" brakes, when he got a flat, had two change two tires just to get back (front left flat, swapped left rear with spare, put good left rear on front.) i don't even know what he'd do now that he has 275's in the back now.
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I made the mistake of fitting my rotors and brakes so that they would clear the Panasport 17s I had on the car. Then I found a set of the Volvo (Polaris?) 17s cheap and bought them. Didn't occur to me that they wouldn't fit, but they didn't. The center section of the the rim was too deep and hit the caliper. Sigh... I sold the wheels to Simon Dodd, the bastard! ;)

I've got 245 in the back and 225s on the front. I haven't even tried putting my space saver spare on the front - it's clearly not going to fit. I carry a couple cans of fix-a-leak in my car and my AAA card in my wallet.

Peter
 
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pgrey said:
I made the mistake of fitting my rotors and brakes so that they would clear the Panasport 17s I had on the car. Then I found a set of the Volvo (Polaris?) 17s cheap and bought them. Didn't occur to me that they wouldn't fit, but they didn't. The center section of the the rim was too deep and hit the caliper. Sigh... I sold the wheels to Simon Dodd, the bastard! ;)

I've got 245 in the back and 225s on the front. I haven't even tried putting my space saver spare on the front - it's clearly not going to fit. I carry a couple cans of fix-a-leak in my car and my AAA card in my wallet.

Peter
Click to expand...

lol thank god for flatfix and AAA. They are with me at all times ;-)
 
Hey Sean.......
brake pressure is plumbed from the brake master to where the resivoir would be on the clutch master. Thus when we apply brakes we are applying through the hydraulic handbrake. Tug on the handbrake and it pumps fluid to apply the rear brakes. I have zero abilities about posting pics and my wife won't let me near her digital camera, so unless one of you takes a shot of it ya won't be getting pics from me.
JL.
 
Snoop Dougy Doug said:
I'd even be willing to bet that the EVO and STI brembo brakes have the exact same mounts as the R (they use the same pads as the R) so you could probably use the same bracket. I've seen complete (all four) EVO and STI brake set ups on ebay.
Click to expand...

I wouldn't be surprised since Brembos are on all types of cars these days (350z, G35, STI, etc.)
 
Does anyone Know the actual piston diameters that are used in the S-60-R calipers ? or piston area (2 pistons,1 side)?
 
Snoop Dougy Doug said:
Dave, why not just cut the line in the middle and flare and use your own SAE fittings.

I have a wilwood porportioning valve that I've had forever that I plan to put to use.

NOW, what I would like to know is: Is there a generic distribution block that would let you keep the front of the master cylinder to the front brakes, and the rears to the rear?

Seems to me, you'll have the same problems that a few of us are having trying to use a 'lineloc'

Oh, I just remeber, Evolve I believe will be offering S60R discs converted to 2 piece floating discs with aluminum hats. Thats what the rumor is (makes sense to me). Probably pricey, but would be probably still cheaper than the EST Porsche 993T big red kit.
Click to expand...

...And you've got to get your act together and take some measurements for backing plates for me. he he. ;-)
 
I do a lot of custom work on Toyota Supra Twin Turbos and once wrote the following rather raggedy article on brake balance that my be appropriate to quote here:

Brake upgrades can set out to try to achieve several objectives.
The commonest are to increase resistance to fade and or increase
braking effort for a given pedal effort. IE, the pads are
pushed against the discs harder for a given pedal effort than
before the upgrade, or the brakes will stop the car from 100 MPH,
hard, for more times before fade sets in, than previously. The feel
from the pedal, that almost intangible quality, can also be addressed
and sometimes improved upon by brake size, or pad material changes, or
brake flexi hose upgrades to something less squashy than rubber.
It's easy to get carried away by the thought of brake upgrades.
The limitation in most cars as to how short a distance they can
stop in is tyre friction. Leaving aside pedal feedback, and fade,
it is almost certain that a Supra on stock Jap spec brakes will
stop in just as short a distance as one with an AP six pot kit on
it, a Brembo kit, Pauls KAD kit, or whatever. It may not feel to
the driver that it does, but usually such is the case if you just
nail the pedal as hard as you can. The fancy kits may *FEEL* to
stop the car faster, due to less pedal effort, and a better bite,
but in reality, if you hit the pedal as hard as you can with stock
Jap spec brakes, UK spec brakes, AP kit, KAD, whatever, the car
will stop in the same distance. Repeat this test 10 times and stock
Jap brakes may be on fire and long since faded, or the fluid boiled,
UK ones may be very hot and bothered, but the upgraded ones will
probably still be working within pad, disc and brake fluid temp
limits. Add in the intangible "feel" factor, and a desire to brake
as hard as possible, using as little skill as possible, but WITHOUT
relying on the ABS to take over, and for sure a well set up brake
upgrade may well allow more finesse.

Herein though lies the rub.

Upgrade only the fronts and the brake balance of the stock car may
well be compromised. Let's take stock brakes. You press smoothly on
the brake pedal with (say) 50 pounds force. The car stops fine. 70
pounds, the fronts are just beginning to lock (car makers ALWAYS aim
for the fronts to lock first, as rear wheel lock makes the car very
unstable and liable to swap ends). The rears are doing as much work
as the brake engineers deemed safe to prevent premature rear lock up.
The ABS cuts in, and maximum retardation has been reached. Now, take
a car with big front discs and calipers. Only 40 pounds pressure now
gives a smooth, lock free and powerful retardation. 50 pounds and the
new, more powerful, (for the same pedal pressure), fronts are locking.
The ABS cuts in. BUT, and this is the crux, those original rear
calipers and discs are still well below the caliper pressure where
they are able to achieve maximum retardation without fear of the
rears locking.

In other words the FRONT brakes are doing TOO MUCH work, albeit without
breaking into a sweat, and the rears are, to exaggerate a bit,
just along for the ride. The BEST scenario is to upgrade front AND
rear brakes, carefully ensuring the original balance of effort at any
given brake pedal pressure remains as designed, but that the more efficient
front AND rear brakes stay cooler for more hard stops, and that old
intangible "feel" from the brake pedal is improved, at lower rates of
driver effort on the pedal. The latter may or may not be good or
desirable, and can be engineered out by changing BOTH front and rear
caliper piston sizes, or pad areas. In a race car the balance would
be adjustable via 2 brake master cylinders, with a driver selectable
change in mechanical leverage effort between front and rear brake circuits,
one cylinder operating the front brake calipers, the other the rear. This
can also be achieved on road cars, but to do so is usually complex and
expensive, especially if ABS and brake circuit failure safeguards are to be
maintained. It is far easier to calculate the caliper and disc sizes, along with
pad area and compound to achieve this, as near as available off the
shelf equipment will allow.

Caveat. I said before makers engineer more effort on the front brakes to
encourage straight line stopping if the tyres are locked up . They err on
the excessive side, as, in the wet, the rear tyres can take a lot more
braking effort than in the dry, due to less weight transfer onto the front
tyres, as they will lock before as much weight is transferred when the grip
of the road surface is reduced. So adding yet more front brake effort worsens
this existing imbalance, especially in the wet. If it were not for the
ABS the front wheels would be locking up very early. On the Supra a
relatively sophisticated ABS allows some effort to be taken off JUST
the fronts, and an artificial and very inefficient balance is returned.
On cars with lesser (1 or 2 channel) ABS, or no ABS at all, a brake
upgrade on just one end of the car can be lethal.

Written hurriedly, and briefly, as my typing speed is terrible, but
hope it helps explain the gist of the potential problems.
 
Eliminating stock reduction valves

To all playing with the S60R brakes conversion......
Thought I would revive this thread and add to it.

I was looking at the OEM Volvo Reduction (proportion) Valves under my 245 and realized the TWO brake lines going in and TWO coming out are all males fittings (whatever normal thread Volvos use). I knew I would need to eliminate these valves eventually if I am going to insert an adjustable proportion valve to control the rear brakes.

A light bulb exploded in my brain and I realized a simple solution..... I could substitute a standard 240 Brake Junction Block in place of the two valves. There are 8 ports on a Junction Block, so 4 of them need to be plugged. This can be done with ATE brake cylinder plugs you can get from Volvo, PN 1387406 (retail about $7 each), or you can use standard 1/8 inch pipe thread plugs with some teflon tape (they will thread in and hold the pressure fine, but need to be cranked in deep).

This is EXPERIMENTAL and I'm thinking it will return my 245 closer to neutral front/rear braking instead of the front biased I have had since I installed the R brakes. At least I will know exactly how it will react with no proportioning at all now and will give me an idea of what, if any, reduction in pressure the rear brakes need to balance things out. We'll see and I'll let you know.
Dave B.
R-brakes015-lores.JPG
 
proportion valves.

Looks good for a no proportioning solution Dave!

Have you considered using the sedan pressure limiting valves? They are rated for a lighter weight than the wagon. Of course the best is to install an aftermarket proportioning valve.
Just wanted to offer another thought for a solution.
Enjoy the brakes!
 
dlot said:
Looks good for a no proportioning solution Dave!

Have you considered using the sedan pressure limiting valves? They are rated for a lighter weight than the wagon. Of course the best is to install an aftermarket proportioning valve.
Just wanted to offer another thought for a solution.
Enjoy the brakes!
Click to expand...

I am considering an aftermarket proprtioning valve, but I think in order to do it right I should eliminate the rear reduction valves first. I don't think compound proportion valves is a good idea.

And I believe it's the wagon reduction valves that offer the highest rear bias. I think installing sedan valves in a wagon would limit the rear brakes more. Makes sense to me since the rear on a sedan is lighter, especially considering GVW specs.

Snoop Dougy Doug said:
Nice dave, looking good.

Maybe if you want I can teach you how to make your own lines and you can clean up the god forsaken mess volvo gave us like me ;)
Click to expand...

I would like to take you up on that.
Dave B.
 
anytime :D

ITs reallllly easy. Mine all held pressure first try out :-D well ... first try in the shop ;-)

Im running a wilwood valve on the front lines. Kinda an inverse of what I should be doing. It'll either work or it wont. If it does cool, if it doesn't I'll remake the lines to the rear, delete the valves and just use the valve back there. Not sure why I didn't but I didn't do it this way this time.
 
Snoop Dougy Doug said:
anytime :D

ITs reallllly easy. Mine all held pressure first try out :-D well ... first try in the shop ;-)

Im running a wilwood valve on the front lines. Kinda an inverse of what I should be doing. It'll either work or it wont. If it does cool, if it doesn't I'll remake the lines to the rear, delete the valves and just use the valve back there. Not sure why I didn't but I didn't do it this way this time.
Click to expand...

That's the thing about you Doug.... you aren't following the rules. You will now be banished for not doing things like everyone else.

Ok, here's a follow up on my elimination of the rear reduction valves. So far, so good. After a few hard and loud brake applications from about 60 mph, the front/rear balance is very close now. And for all you who thought that removing the valves would make the rears lock-up first (including me) we were all wrong. The fronts still lock first, right before the rears. I might eat my words later, but I may not need to go to the trouble of an adjustable proportion valve. Testing to continue, but all in all, my 245 now pulls fillings when you stomp the brakes.
Dave B.
 
Dave - I did something similar to the rear brakes on my '77 242, except instead of using a junction block and plugs I just used a female/female coupling on each line. On that car I had EXCEPTIONAL brake balance, but when I tried the same thing on my buddy's '80 244, it locked up the rears quite badly so we removed them. Apparently the '75-'77 used (or mine had installed) the smaller 142 rear calipers 'cause it would NOT lock the rears. I got alot of flak for it at the time but I was very happy with the balance.

I also reinforced the control arms and trailing arms a couple of years ago, with extremely positive results. I did them just like JL spelled out earlier, but I think I used 14 gauge sheet metal instead of the thicker 10 gauge (or whatever) used in the rest of the arm. It's basically a membrane used to keep the shape of the heavier section more stable. It works, anyway, and I'm not abusing them like you guys can.

Like Philip, I don't spend alot of (any) time on a track or roaring down a mountain, so extreme brakes are only a "wow" factor for me right now. Having the ability to stop NOW from speed, once, is enough for me right now. Anything more would be added cost, weight, and would basically be unused. I could use some upgrades to the stock system, but it works pretty darn good for me right now.

However, one day I might need 'em, so keep the cutting edge sharp, guys! Good work!
 
Matt Dupuis said:
Dave - I did something similar to the rear brakes on my '77 242, except instead of using a junction block and plugs I just used a female/female coupling on each line.
Click to expand...

I haven't found a source for a female/female coupling with the correct thread for those lines. Do you know one?

Matt Dupuis said:
On that car I had EXCEPTIONAL brake balance, but when I tried the same thing on my buddy's '80 244, it locked up the rears quite badly so we removed them. Apparently the '75-'77 used (or mine had installed) the smaller 142 rear calipers 'cause it would NOT lock the rears.
Click to expand...

Maybe that 244 would have benefitted from fitting a pair of 245 reduction valves. Maybe the extra weight of the rear of my 245 is what makes the difference between the two.
Dave B.
 
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dbarton said:
I haven't found a source for a female/female coupling with the correct thread for those lines. Do you know one?
Click to expand...
The thread was right but the flare was wrong - it was a double flare vs. our reverse flare, or something like that. No matter, it threaded in and held on tight. It was brass, so that probably helped the seal. I just got them from the local auto parts store... I soft clamped them to the body to replace the support the hoses got from the limiter valves. Your use of the distribution block/failure switch is brilliant, though - but I imagine that finding the plugs was a bit of a headache.

dbarton said:
Maybe that 244 would have benefitted from fitting a pair of 245 reduction valves. Maybe the extra weight of the rear of my 245 is what makes the difference between the two.
Click to expand...
Exactly what we were thinking at the time, but we never bothered trying any out. I may do that on my current car, though. The problem is that after 20-30 years of people NEVER changing the brake fluid, most of those limiter valves are probably rusted right tight. Anyway, they only shut off the pressure to the rear calipers above a certain PSI, and they do no pressure reduction below that. Until you get a significant amount of weight transfer to the front, the pressure distribution granted by the caliper piston areas is enough to keep the rear brakes from locking.

Extra weight in the rear of your car, plus the lowered stance giving less weight transfer to the front, plus the stronger front brakes have probably all combined to remove the need for those limiting valves. In fact, I'd be curious to try it out on a stock tired, stock sprung 245 with stock brakes - I'm thinking it would still be fairly well balanced. It was pretty light in the tail on a stock 244...
 
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