e34 remote brake booster install

[JGood]

I've got the e34 remote booster linkages that I'd like to try to install. I'm not an engineer and the brake linkage is a pretty critical part of the car, so I'd like to discuss my options a bit.

The stock firewall mounted bracket seems to bolt in fine to the stock location and the stock pedal connects right to it. However, I believe with the engine installed, it would be occupying the space that the cylinder head needs to go. Also, the bottom of the pivot contacts the steering shaft.

One option would be to shift the whole thing over, to clear the engine and the steering shaft. I'm not sure how the connection to the pedal could be made on the inside of the car, however. Ideas?

Another option that I see is to mount the bracket in the stock location, and chop off everything below the pivot. Then connect the rod that goes to the booster to upper pivot attachment point. Basically the pivot would just be acting as a stabilizer, and it would be a straight rod from the pedal to the booster. I believe I read someone saying it is not recommended to so a straight rod to the booster, though. I can't really see why. Your thoughts?



EDIT: I see that I am unable to spell the word 'directly'. Doh.

[noid]

From the way I see it, when you push the upper rod, it pushes the lower rod in the opposite direction, attaching the bottom rod to the top would do the opposite of what you need it too.

Its hard to tell from the picture, but is the center of the metal plate that connects the two pivot points together mounted at its center? Because if its mounted higher of center then when the top rod moves, the bottom rod moves even more in distance.

[JGood]

From the way I see it, when you push the upper rod, it pushes the lower rod in the opposite direction, attaching the bottom rod to the top would do the opposite of what you need it too.

Its hard to tell from the picture, but is the center of the metal plate that connects the two pivot points together mounted at its center? Because if its mounted higher of center then when the top rod moves, the bottom rod moves even more in distance.

In the factory setup, there is another bracket with a pivot assembly at the booster location as well. So the force is transferred back into the forward direction. I'm considering bypassing the entire pivoting assembly, and just use the pivots as stabilizers... the bar will move and swing the pivots, but they won't actually do anything other then stabilize the bar, because it's essentially providing a straight connection from the pedal to the booster, just like the stock e30 (but much longer, of course).

To answer your question, the lever in the pic does not pivot around the center distance between two rods. But I'd assume the lever at the other end is designed with the same lengths, bringing total pedal travel back to what it would be if it was just a straight rod, with no pivots.

Here is how it's set up in an e34:

[JGood]

Posting this tidbit of info here as I feel it may be relevant at some point...

"...from my days designing brake actuation components, it was generally assumed that anything past 3 deg of pushrod misalignment to the centerline of a vacuum booster was a risk for damaging the booster internals."

From:

http://www.corner-carvers.com/forums/showpost.php?p=880488&postcount=29

So regardless of my setup, I do need to get the rod on some sort of pivot directly in front of the booster that creates a straight line into the booster if I want it to have a long life.

[JGood]

Garey, if you're reading this, how did you intend to connect the brake pedal to the linkage when you were mocking up your setup? Looks like you moved it over and down about 4 inches on the firewall, and this seems to be the best way as it leaves the proven e34 system intact. I just didn't see an easy way to connect the pedal to the linkage.

[bmwmech1]

You have to move the pedal attachment point to the opposite side of the pedal and down. The drawback is it will increase your pedal effort, because you're reducing your leverage effect of the pedal. By how much I don't know, since I abandoned the E34 setup before I was able to drive the car. This looked like the best route to me as well, since it does keep everything intact and functioning in the exact same way as designed, with the exception of the brake pedal connection point/height. There may be another solution, but I stopped pursuing it to early to have any more ideas than that one. And you are right about bolting the knee bracket to the original E30 booster/ MC location... the cylinder head will not fit. I moved it towards the wheel house and down, so the top left bolt went through the bottom right hole, as looking at it from the engine bay side of the firewall. This gained the clearance necessary and still allowed mounting all of the components in a functional way...

Garey

[JGood]

You have to move the pedal attachment point to the opposite side of the pedal and down. The drawback is it will increase your pedal effort, because you're reducing your leverage effect of the pedal. By how much I don't know, since I abandoned the E34 setup before I was able to drive the car. This looked like the best route to me as well, since it does keep everything intact and functioning in the exact same way as designed, with the exception of the brake pedal connection point/height. There may be another solution, but I stopped pursuing it to early to have any more ideas than that one...

Garey

Cool, thanks. I wasn't sure if there was room on the other side of the pedal, with the clutch pedal being so close. I'll take a closer look at it.

I suppose one way to reduce the pedal effort would be to simply drill another hole in one of the pivoting pieces, and mount the rod slightly up or down, to reduce the leverage. If it's even a problem.

[Teaguer]

I will watching progress on this as I just picked up this set-up for my M3 today:



Although I have the booster delete from Lee i still wanted to try e remote booster set-up as well since I have big brakes and am unsure of the required pedal effort and/or feel.
I couldn't pass this up this weekend as it was super duper half-off sale at Pick-n-Pull.
I was able to yank the whole assembly all for $17! :D

I did notice when researching this remote booster that the e34 and e32 pedal is right inline with the frame rail that the brackets and linkage run along.
And figured I would just move the linkage to the outside of the pedal pivot.

[bmwmech1]

^^^ Is the s14 still in your M3 or have you swapped to an S5X? I'll be curious to see how this setup works out in you car. If you can keep the knee bracket close to the factory location, this could be a nice setup without too much modding to make it work and look nice... I'll be looking for some updates, as you go along...

Garey

[JGood]

Well, I can't find a reasonably easy way to get the brake linkage connection on the other side of the brake pedal. It would require relocating the clutch master cylinder and potentially the throttle linkage. I'd rather go with an aftermarket boosterless pedal setup before I did that.






Here was my original idea. Linkage runs directly to the booster.




Here would be a way to keep it tucked in towards the wheel well more. Just connect the inner pivot to the out pivot, so they move together.





Or connect it at the bottom like stock, and use the pivot on the booster side as well.






Or turn the thing sideways?







My main question is, is there even room for the firewall mounted pivot assembly with the engine in place? Because if not, then all of those ideas are useless.


I came across this, which was my basic original idea, minus the firewall mounted pivot. It uses the booster-side pivot to stabilize the bar and probably keep the 0 degree entry into the booster. I'll probably end up doing this.



It looks like he just took a length of steel square tube, welded some sort of connection on the end. My thought would be to weld a nut on the end, and thread in a male heim link that will match the width of the factory fork connections. That would allow for movement without binding, would be fully adjustable, and would be fail-proof during compression. Thoughts?

[Teaguer]

Or connect it at the bottom like stock, and use the pivot on the booster side as well.

^This is sort of the idea that I was thinking of implementing on my set-up.
Either modify the E34/E32 firewall mounted pivot point/rod attachment or just come up with a whole other pivot set-up altogether .....similar to the one the Garret and his dad used and sell for their LS1 swap kit.

As far as there even being room once the BMW engine is in ...maybe this thread over on Bfc will help as I posted a few pics of BMW V8 cars in there.

https://www.forums.bimmerforums.com/forum/showthread.php?t=1698125

Garey, I bought my car sans S14 with the anticipation of throwing in a S50 that i had.
After assessing other issues needing attention i dismissed the typical 24v swap and sold off the S50.
I've now decided on and started acquiring parts for a 16v swap. ;)

[bmwmech1]

Garey, I bought my car sans S14 with the anticipation of throwing in a S50 that i had.
After assessing other issues needing attention i dismissed the typical 24v swap and sold off the S50.
I've now decided on and started acquiring parts for a 16v swap. ;)

Alright, quit being so cryptic, lol! 16V what? Obviously, if it were an S14, you'd have said so... so... 16V what, lol?

Garey

EDIT: I clicked on the link to the Bfc thread in your post and low and behold, there were pictures of my initial mock up of the E34 setup I sold to Will, lol! Had I continued on with that equipment, I have no doubt it would have gone through 3-4 iterations before it was finalized, but the hardware is usable and it keeps you from having to reinvent the wheel. If you're doing a 16V swap, you should have few issues with space for whatever you come up with...

[bmwmech1]

...My main question is, is there even room for the firewall mounted pivot assembly with the engine in place? Because if not, then all of those ideas are useless...

If you mount it like I said, it clears, but leaves you with the pedal arm connection dilemma. Any of the ideas you pictured won't fit, not enough space... remember when you were at the shop and looking at the space between the left cylinder head and the firewall? You can only get 2 fingers between them where the MC hole is. This guy's thread has some good stuff in it, excluding the motor mounts... http://forums.bimmerforums.com/forum....php?t=1366630 He machined a really slick lever setup from aluminum and steel, with brass bushings and the whole bit... Take a look and maybe it will get your brain working on a solution... or what about a lever assembly inside the firewall...

Garey

[JGood]

Thanks Garey. Hard to remember the details on a build like yours, I'm too busy drooling over the whole thing. Plus I know your engine is back a bit further then mine will be.

Do you think it would fit if I moved it straight over to utilize the 2 far side holes, but not down at all? Like this:







If so, then I have a plan. I can space the clutch master cylinder over about an inch using spacers and longer bolts. The brake linkage can fit in between the two mounting bolts of the master cylinder, and be attached directly to the pedal via some sort of welded on tab. If I do this, the only thing that would need seriously modified is the accelerator linkage, which I have a few ideas for. That linkage uses a long curvy rod that gets in the way of the master cylinder in it's new position. The master cylinder can't be easily tilted in any direction, only side to side. It seems to require an exact angle in relation to the pedal that will allow it to not arc, otherwise it binds. I really don't want to mess with it. That's also why I couldn't get my pivot assembly shifted down like yours was, it occupied the space the master cylinder is supposed to be in.

But, before I go chopping up the firewall that I just spent a month rebuilding, I'd like some input as to if the bracket will fit in that position, and clear the cylinder head.

[bmwmech1]

Well,, if the clutch master is stable enough, cantilevered over like that, it looks do-able. Cut the tab off the right side of the brake pedal and move it to the left side, for your connection. Based on the 1 picture I have of the exact area, it looks like it will clear the valve cover, without issue. I you look closely, you can see the knee bracket in place, mounted to the lower-most right hole and see the 1/4-1/2 inch between the VC and the bracket. It should have the same clearance in your mounting position, just higher...



IIRC, the reason I moved it down also was so the knee bracket would sit on the frame rail, which made the setup very sturdy, but complicated the rest of the connections under the dash. The "foot" of the knee bracket could always be extended to meet the frame rail. Make sure you write down all the measurements and dimensions of what you change or make/modify. Looks like there may be more than a few that would like the info...

Garey