A different approach to the v8 swap brake booster...

[mr walker]

LOL. Guys, I've got to be honest...I was being sarcastic about mounting it in the trunk. But you raise a valid point that folks may be looking for additional engine bay room.

I was under the impression that the linkage setup was a PITA...is the whole problem with the V8 braking setup an issue of space for the booster? Or do the linkage and booster kind of "negatively compliment" each other (i.e. in order for the booster to stay inline with the linkage, the booster must remain towards the middle of the engine)?

[JGood]

There's a thread discussing the e34 linkage setup in an e30 in this subforum, I just finished mine up.

If your planning on keeping the e34 booster and bracket in that location in the front of the bay, I think you're creating more work and failure modes by doing a hydraulic linkage vs mechanical. The linkage itself basically bolts right in. It's fitting the booster bracket that's a PITA. Then it's just the pedal box mods, which you'd have to do anyway to run an internal M/C.

[Jonsku]

If your planning on keeping the e34 booster and bracket in that location in the front of the bay, I think you're creating more work and failure modes by doing a hydraulic linkage vs mechanical. The linkage itself basically bolts right in. It's fitting the booster bracket that's a PITA. Then it's just the pedal box mods, which you'd have to do anyway to run an internal M/C.

I have to disagree with this.

Fitting the E34 linkage (shortening and cutting a bit) is not too hard a job. Only challenge is doing the offset (as the brake linkage will be about 10cm to the left of the car from the brake pedal). The offset can be done either on the pedal (considering the space for clutch pedal as well) or as a separate linkage on the firewall.

I've done both and I'd say they are equally hard as both solutions have their own pros and cons.


Brake servo won't take too much space from the trunk so locating it there would be quite good idea actually. Helps with the weight distribution as well :)



Any ideas on good cylinder sizes? :)

[JGood]

I have to disagree with this.

Fitting the E34 linkage (shortening and cutting a bit) is not too hard a job. Only challenge is doing the offset (as the brake linkage will be about 10cm to the left of the car from the brake pedal). The offset can be done either on the pedal (considering the space for clutch pedal as well) or as a separate linkage on the firewall.

Right, but modifications will need to be made to the pedal box in order to mount a brake master cylinder to it (safely), that are likely just as challenging as the modifications for offsetting the brake linkage pick-up point as with the e34 setup. That was my point. The front booster bracket and the pedal box are really all that need modified for the e34 booster setup, and you'd have to do that stuff anyway to get the hydraulic system fitted, if you want to keep that location. So you'd be removing the only "bolt-on" part of the e34 assembly, and replacing it with a hydraulic system that's going to require some $$$/research/fabbing.

To be honest, moving the clutch cylinder over and welding a tab on the other side of the pedal box is really pretty easy.

However, as you said, the trunk mounted setup would be nice, and a very good reason to go with a system like this. I'll be watching this thread to see how it turns out.

[LJ851]

Any ideas on good cylinder sizes? :)

M/C size shouldn't matter. As long as the master and slave are the same size you will have no ratio.

I like this idea, but my only concern would be the two added single circuit M/C's and that if either of them fail you lose all braking. Prob would not be legal for any racing organization.

[Exodus_2pt0]

I like this idea, but my only concern would be the two added single circuit M/C's and that if either of them fail you lose all braking. Prob would not be legal for any racing organization.

This is exactly why reservoirs are seperated front/back nowadays. That way if you spring a leak, you don't lose both front and rear systems.

Leaving all of your braking capabilities in the hand of one hydraulic circuit without any "plan b", would be a little scary at 100mph.

Aside from that, I love the idea. If there is a way to incorporate a fail safe, I would consider this for my own future plans.

[mr walker]

This is exactly why reservoirs are seperated front/back nowadays. That way if you spring a leak, you don't lose both front and rear systems.

Leaving all of your braking capabilities in the hand of one hydraulic circuit without any "plan b", would be a little scary at 100mph.

Aside from that, I love the idea. If there is a way to incorporate a fail safe, I would consider this for my own future plans.

Yeah, I actually anticipated this being the main resistance to my idea, rather than it being complicated or difficult to fabricate.

Seeing as how we all rely everyday on a similar setup for the clutch, and for some people the hand brake for drifting or whatever, it can be tempting to go down this route. But we obviously can't forget that this must be FAR more fail proof than either of those. After all it's not uncommon to see people with clutch slave cylinder problems on this forum...given those parts are now a 1/4 century old now.

[LJ851]

A failed clutch slave will not kill you. That being said, my '62 International Scout has single circuit brakes and i drive it.

[2002maniac]

[328ijunkie]

Yeah seems like kinda sketch to rely on hydraulics to get the pedal power to the booster/mc

[nrubenstein]

Yeah seems like kinda sketch to rely on hydraulics to get the pedal power to the booster/mc

No sketchier than any of the remote booster linkages that I've seen. Doing it properly will be a challenge though.

[kristov]

I have to disagree with this.

Fitting the E34 linkage (shortening and cutting a bit) is not too hard a job. Only challenge is doing the offset (as the brake linkage will be about 10cm to the left of the car from the brake pedal). The offset can be done either on the pedal (considering the space for clutch pedal as well) or as a separate linkage on the firewall.

I've done both and I'd say they are equally hard as both solutions have their own pros and cons.


Brake servo won't take too much space from the trunk so locating it there would be quite good idea actually. Helps with the weight distribution as well :)



Any ideas on good cylinder sizes? :)

How is the pedal feel compared to stock E30 pedal feel?

[BruceBe]

Putting in a remote hydraulic system introduces a single point of failure for the entire braking system. If the hydraulics between the master/slave become compromised, you lose all brakes in the vehicle.

Food for thought.

-Bruce

[glucklich21]

Not any different if you were to loose a brake line or master cylinder really. I'm looking into this after Lee @ Massive Brakes posted this:



I would want to use solid stainless steel lines going to the hydroboost, not braided. We use it in the oil field and it's good for 5000 psi. I trust it a little more. ;)

[JGood]

Not any different if you were to loose a brake line or master cylinder really.

From my understanding...

It's completely different. The master cylinder has two separate reservoirs, feeding two separate circuits, and the compression of the brake pedal, and therefore the individual pistons, is mechanically activating each circuit individually regardless of the other circuits condition. If you blow a front brake line, you still have rear brakes, and vice versa.

With a remote system, if you blow that single line, you lose it all, there is no backup to help you slow down.