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Big Brakes

what about swapping the proportioning valve from another volvo?
the jtr v8 book lists the following:
gas 244 = 483 psi
gas 245 = 710 psi
gas 264 = 355 psi
gas 265 = 483 psi
diesel 244 = 355 psi
diesel 245 = 710 psi
not sure if it helps, but i'll search for some adj ones also.
any thoughts on a bracket group buy? i'll go around picking up cans or sell oranges on the off-ramp for the money.
 
Careful about thinking that we are soooo much more clever then the engineers about front suspension geometry. Be damned sure that angles of the control arm are exactly the same as the tie rod through the up-down travel in front suspension.

My adjustable brake bias is next to my hydraulic hand brake for the rear wheels. Turn the knob clockwise for more rear bite. I forget the brand. I would prefer to have one of the bias balves with a handle that moves through eight (or whatever it is) positions to see exactly where it is set at a glance. The knob has to be done by feel in the brakes.

My front brakes.......Rotor and hat are six pounds per corner. AP calipers are much lighter then stock. Do weigh everything before and after. You will be shocked at the improvement in predictability you end up with for braking and handling when unsprung weight is reduced by several pounds per corner. When you are more comfortable with things you will be easily able to drive right up to the edge cuz you will not be afraid of the car biting you in the ass.

Having the car bite you in the ass: BAD.
John Lane
 
John, how hard was the hydraullic handbrake to set up?

Does your bias valve adjust pressure to the rears or the fronts?


Oh, on terms of improving the A-Arm. Ryan (volvorod82 or somethign like that) can speak VOLUMES about that. At the last BBQ, as Ryan was backing into a parking spot he heard a LOUD clunk and the front DS tire had rotated forward and jammed up in the wheel well.

Turns out, he had a crack develop from the ball joint (between the 3 bolts) straight back on the a-arm and it split in half. thank GOD it did it when it did, 2 minutes earlier he was moving down the freeway at ~ 80mph. He was REALLY lucky.
 
Brake bias is always done through the rear brakes.

My hydraulic handbrake consists of a clutch master cylinder plumbed into the single brake line that goes to my rear brakes. The fluid goes in where one would have the resivior for the clutch master and comes out the normal spot. The handbrake handle is modified to operate a rod to push on the master cylinder which is mounted to a bracket welded to the tunnel behind the E-Brake handle.

When we turn up the excitement our cars are capable of we MUST be LOT more diligent about watching things. The Control arm mod I mention makes a BIG difference.

JL.
 
Snoop Dougy Doug said:
Dave, why not just cut the line in the middle and flare and use your own SAE fittings.

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?
Click to expand...

Flaring my own lines is an option, but.... I would rather not spend the money on the tools to use once if there is an adapter or metric valve available (there are several different types of brake line flares and a separate tool needed for each type).

About the distribution block.... you can use the one you have. You will need to eliminate the diagonal brake circuits. You can move the lines around to accomplish that. You will also need to disable the warning light. And Volvo has threaded plugs that fit the extra holes you will have when you go to one line per front wheel... and/or one line for the rear circuit.
Dave B.
 
dbarton said:
Flaring my own lines is an option, but.... I would rather not spend the money on the tools to use once if there is an adapter or metric valve available (there are several different types of brake line flares and a separate tool needed for each type).

About the distribution block.... you can use the one you have. You will need to eliminate the diagonal brake circuits. You can move the lines around to accomplish that. You will also need to disable the warning light. And Volvo has threaded plugs that fit the extra holes you will have when you go to one line per front wheel... and/or one line for the rear circuit.
Dave B.
Click to expand...


Really? How very intresting. Seems to me, going to S60R front brakes, with modifying the dizzy/block to keep the fronts exclusive to the fronts and rears exclusive to the rears (in terms of the master cylinder) would also let me finally set up my LineLoc the right way.

JL, do you have any pictures of your hydraulic handbrake? So it just actuates the OEM calipers? So basicly the "handbrake" is its own master cylinder (ofcourse) but it ties into the same caliper/rear brakeline? Can you lock the handbrake... ie let it function like a normal "parking brake"?
 
n xntrx volvo said:
what about swapping the proportioning valve from another volvo?
the jtr v8 book lists the following:
gas 244 = 483 psi
gas 245 = 710 psi
gas 264 = 355 psi
gas 265 = 483 psi
diesel 244 = 355 psi
diesel 245 = 710 psi
not sure if it helps, but i'll search for some adj ones also.
any thoughts on a bracket group buy? i'll go around picking up cans or sell oranges on the off-ramp for the money.
Click to expand...


This is some excellent info. Now, all we need to know is which direction those valves work. Does higher pressure mean more restriction or less. By analyzing the info, we see that the Wagons had Higher PSI, except for the 265, which is a V6 and heavier in the front, but not much. The Diesel 244 though has a fairly low pressure, yet the diesel motor is well known to weigh more in the front, thus needing stronger front brakes. My inclination, based on reading, would be that the more weight in the rear, would need higher pressure in the rear to account for the weight and even it out for the weight over the rear wheels. It almost makes the wagon seem like the better candidate for big brakes. So, lets start with this and see where it leads. After quickly reading re-reading "Brake Systems, OEM and Racing brake technology" by Mike Mavrigian and Larry Carley, they state that cars with larger front weight bias, like pickup trucks and minivans and front drive cars, can have up to 80-90% front brake Bias. Bias is also affected by the type of rear brakes used. If you have drum brakes in the rear, they are self energizing, and thus, need less pressure to apply a certain amount of force. Discs on the other hand, are not self energizing, and need more pressure to apply the same amount of force. So, since we have rear discs, and they are a good solid twin piston design with a 11" diameter, rear drive and decent front to rear bias, our cars most likely have more rear bias in the brakes than say a truck or minivan. Now that I have much larger front brakes, I have fully shifted the bias heavily to the front. If I had to guess, and I am, I would say I have gone from 65% front bias to 80-85% front bias. I would need to increase the rear bias by about 15% or a little more. Testing of course would prove this correct or wrong.

The break down of the valves goes in this order

264/244diesel......355 PSI
244/265.............483 PSI
245/245diesel......710 PSI

I know that I should have a 483 valve, but that could be wrong since I have a 242 and Dave B should have a 710. We do plan on pulling a few junk yard valves, and may experiment there first. Those parts are very easy to get. Removing the two rear valves is pretty darn easy to do.

"Holy Huge brakes Volvoman, we must get to those proportioning valves to avert the deadly front bias we have created!!!!!!!!"...."To the Volvo-Cave Volvoboy!!!!!!!!!!!"

Cheers

Paul Jones

PS. Frued did slip, then fall, then found a quarter ;-)
 
Snoop Dougy Doug said:
JL, do you have any pictures of your hydraulic handbrake? So it just actuates the OEM calipers? So basicly the "handbrake" is its own master cylinder (ofcourse) but it ties into the same caliper/rear brakeline? Can you lock the handbrake... ie let it function like a normal "parking brake"?
Click to expand...

I have Porsche (Brembo) rear calipers in my toy. Would work exactly the same with any caliper.
We also modified the handle so that the ratcheting mechanism will lock when you push the button down (pull the handle up and push the button) so that it could work as an E-Brake, but it is hydraulic and I would not want to trust a hydraulic anything with not bleeding down overnight just as a matter of course.

Somewhere we have photos, but I'll be damned if I know where. When we did this the digital camera had not yet come to be.

The hydraulic handbrake is for when you need to rotate the rear end NOW at any speed. Like acute turns like you see in rally.

JL.

JL.
 
Snoop Dougy Doug said:
So the rear valves are whats different? Paul/Dave, how are Daves brakes feeling in comparison to Pauls? How about trying Daves rear valves first?
Click to expand...

Both Paul and I have driven each other's cars briefly to see how the R brakes felt. There was not a lot of difference in feel and front-brake-lockup sensitivity seemed about the same. The minor difference could be attributed to the difference in pads (I have EBC Greens, Paul has OEM Volvo). I am surprised to read about such a big difference in the proportion valve settings between a 244 and 245. I would not have expected such a difference.

The best test was of course on the track at Thunderhill. I think the hardest place on that track for brakes was coming into turn 8 (the left hairpin)... braking as hard as you can from 80 or 90 mph down to U-turn speed.

I remember that corner well last year... my 245 had drilled/slotted Brembos with stock calipers, Mintex pads and Ate Super Blue. The brakes worked fairly well, but clearly were maxed out coming into that corner. I was running Bridgestone S-02's, and had I been running sticky competition tires then I think the brakes would have suffered poorly.

This year on the same corner, same S-02's, I had to be very careful to avoid overpowering the tires. I had to be a lot more light-footed with my brakes. Part of that is the front bias we need to fix, and part of it was the brakes just plain doing a better job.

But my impression of the brakes at the track was that I could have very easily run much stickier tires at much higher speeds without making the brakes even sweat. They worked very well... 22 lb. rotors and all.
 
man, I thought only my 740 locked up rears first. I can't figure it out. My pedal is sooooo light and if I have to stop too fast the DS rear locks right up? Any ideas out there? I would like to go bigger on the front and have been looking into going R up front. Volvo mechanic friend is doing the same so we are needing brackets. Josh
 
Snoop Dougy Doug said:
Called my local dealership... think I'll be ordering some calipers soon before Volvo realize they are GIVING those calipers away! I'll get the discs through Frank @ EST so he can cross drill them for me.
Click to expand...

I hope you're getting a better deal than I was offered on the rotors. EST quoted me over $200 per rotor for either a cross-drilled version or slotted version. I ended up having a local machine shop do mine for $25 each.
Dave B.
 
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