Hydro ==> Vacuum Boost Brakes UPDATE OCT 2015

[DangerWillRbnsn]

Well, that was easy!

I started at 10am this morning, on the dot. I finished the job at 5pm... so 7 hours total. However, I stopped for an hour lunch, and I spent an hour running errands looking for barb fittings and such. I spend a half hour cleaning up the 'new' parts with de-greaser and the pressure washer. In addition to simply swapping the hydro ---> vacuum, I also installed the BBK rotors/calipers, as well as the 25mm master cylinder.

All in all, it was 5 hours of actual work - at a leisurely pace. If you are simply doing the hydro ---> vacuum, you probably only have 3 hours work.

The worst part was drilling/tapping the manifold. I highly recommend swapping manifolds. Drilling the manifold, no matter how careful you are WILL send aluminum shrapnel into your intake. I made a nice little setup with the shop vac, and removed the throttle body to insert the vac down into the manifold... and STILL had aluminum all over the intake. I probly spent a solid hour alone drilling/tapping/vacuuming/cleaning debris.

Anyway - I am happy with the results. NO MORE LEAKS!!! I am most excited about that. Also, the pedal feel is acceptable. It is progressive and provides good feedback. I will admit, the hydro setup felt more smooth but as stated, vacuum brakes are on 90% of the cars on the road and the feel is not all that different.

I highly recommend the swap, and I have to say THANK YOU Adam for posting this up.

BTW, if anyone is interested in a swap, I am happy to pull all the parts and create a 'kit'. I believe I can get everything needed for about $120, plus shipping (keep and tap your manifold, or $160 if you need a new manifold) as there are plenty of e28's and e30's in my local yard.

[pleasefixitup]

hydroboost is too much for me.



in doing my swap from a 528seta to a m30b34. I was not going to go hydroboost too. just take the existing brake system and make it work for my motor.

just make sure you check out a tapping website because it's a process.

1. find ending size
2. drill one hole
3. drill hole bigger
4. insert tap
5. wrap fitting with teflon tape
6. insert fitting

I think I searched tap size or something and it had a chart that I used for each of those steps.


http://www.tkolb.net/chart/NPT_DrillSize.html

thats not the exact site but I used something similar.

shouldn't take anyone longer than 15 minutes.

[ldsbeaker]

Well, that was easy!

I highly recommend the swap, and I have to say THANK YOU Adam for posting this up.

My pleasure, Shane.

If you wouldn't mind, could you take a photo of your hose barb setup and provide details on what you purchased so that I can add it to the original post? I'll make sure you are credited with the information.

[DangerWillRbnsn]

hydroboost is too much for me.



in doing my swap from a 528seta to a m30b34. I was not going to go hydroboost too. just take the existing brake system and make it work for my motor.

just make sure you check out a tapping website because it's a process.

1. find ending size
2. drill one hole
3. drill hole bigger
4. insert tap
5. wrap fitting with teflon tape
6. insert fitting

I think I searched tap size or something and it had a chart that I used for each of those steps.


http://www.tkolb.net/chart/NPT_DrillSize.html

thats not the exact site but I used something similar.

shouldn't take anyone longer than 15 minutes.

Drilling and tapping a manifold OFF the car is simple, and yes - would only take 15 minutes or so.

Doing the job ON the car is much more difficult. Besides the tight working space, you'll have to improvise a way to stop all that metal from entering the engine. Failing to do so will destroy your motor. And THAT is why it took an hour to do. Even with my shop vac setup down the throttle body, I found copious amounts of aluminum shards down the #2 runner. I'm really glad I decided to check, instead of just trusting my shop vac.

Well, that was easy!

I highly recommend the swap, and I have to say THANK YOU Adam for posting this up.

My pleasure, Shane.

If you wouldn't mind, could you take a photo of your hose barb setup and provide details on what you purchased so that I can add it to the original post? I'll make sure you are credited with the information.

Absolutely, give me a little bit and I'll get pics and descriptions of the parts needed.

[ldsbeaker]

Well, it's been a year since install. At least 10k miles, including the hammering at RTT 12, and a trip across the country.
ZERO issues. Literally. I haven't even LOOKED at the system except to clean it from road/dust/engine grime.
Matter of fact, this was the first step towards deleting power steering. So, now you know.

p.s. my driveway LOVES me.

p.p.s. Zach? Zaaaach? Come to the dark side! We have cookies!

[Devinder]

I want to do this on my M5. The heater valve is in a different location and it seems to interfere with the vacuum booster. I've heard of using a smaller diameter booster from a 944 but then there are other parts to adapt. Any ideas? Anyone done this with a S38 in there -- maybe someone who swapped an S38 into an eta body?

[ldsbeaker]

I want to do this on my M5. The heater valve is in a different location and it seems to interfere with the vacuum booster. I've heard of using a smaller diameter booster from a 944 but then there are other parts to adapt. Any ideas? Anyone done this with a S38 in there -- maybe someone who swapped an S38 into an eta body?

There was enough flex in the rubber coolant lines for me to just stow it out of the way. As far as a permanent solution, I am not that familiar with S38 cooling systems, but there are some space issues. And I believe there is someone who put an S38 into an eta body that posted not too long ago, within the last month... Or maybe it was a car for sale.

[Bimmerguy2002]

I want to do this on my M5. The heater valve is in a different location and it seems to interfere with the vacuum booster. I've heard of using a smaller diameter booster from a 944 but then there are other parts to adapt. Any ideas? Anyone done this with a S38 in there -- maybe someone who swapped an S38 into an eta body?

PM me a couple of pics of your firewall near the head and hydrobooster and i can tell you what you may be able to do using e28 parts.

[Mike W.]

I don't know if Jbort kept the vacuum or went hydroboost, but he has a S38 in an eta body.

[Devinder]

Mike, I forgot about Bort. I haven't seen him in a long time.

Matt, thanks -- here are some pictures that might show what you're looking for. I can take more specific pictures later.

[Bimmerguy2002]

Thanks Devinder, will shoot you a PM tomorrow when i get home in the AM.

[ElGuappo]

Mike, I forgot about Bort. I haven't seen him in a long time.

Matt, thanks -- here are some pictures that might show what you're looking for. I can take more specific pictures later.

Devinder, I'll be up at JBorts on Saturday helping im install his new 10:1 motor and 1.3 swap.
I'll try to remember to take a pic of the //Meta, shoot me a text before 2pm to make sure I remember.

[Cupholder Zealot]

Mike, I forgot about Bort. I haven't seen him in a long time.

Devinder, I'll be up at JBorts on Saturday helping im install his new 10:1 motor and 1.3 swap.
I'll try to remember to take a pic of the //Meta, shoot me a text before 2pm to make sure I remember.

Ooohh I wish i could check this out. I'll be heading to Tahoe that weekend, but will be with a friend.

[ElGuappo]

FYI the //Meta was a FULL conversion, so its hydroboost.
He estimates the plenum would keep a vacuum booster from being installed.
Only 1 way to find out!

[tibu68]

I own a euro 635CSI and I have converted it to vacuum booster . I have just finished and everything fits ok. I will post some pictures later.

I have had some issues when bleeding the steering system. I have filled the tank with ATF and moved the steering wheel from left to right over 10 times. The steering pump is still noisy and I can see a lot of bubbles in the tank. What´s next? Insist on this procedure?. Something wrong?

Thanks in advance from spain and sorry for my english

[DangerWillRbnsn]

I own a euro 635CSI and I have converted it to vacuum booster . I have just finished and everything fits ok. I will post some pictures later.

I have had some issues when bleeding the steering system. I have filled the tank with ATF and moved the steering wheel from left to right over 10 times. The steering pump is still noisy and I can see a lot of bubbles in the tank. What´s next? Insist on this procedure?. Something wrong?

Thanks in advance from spain and sorry for my english

Your English is fine.

I had the same issue when I first finished mine. In my case, the PS pump went bad. I thought it was just a major coincidence in doing the conversion - but now hearing you have the same issue I'll reconsider.

You definitely have a leak in the system somewhere. THe pump is pulling air. Check your lines, pump, and such.

[tibu68]

I have driven the car 30 km aprox. and everything is fine now . may be it is a question of revolutions.

I am very satisfied with the result. The car brakes perfect and I can´t see any difference with the steering.

[shagrath]

This is a great thread in case I get another 535iS again.

[tibu68]

Some photographs of the process:

Everything out



Something is missing here



I could use the high pressure pipe which connected the steering box with the "bomb". Now it connects the steering box with the pump. Lenght is just ok. Here you can see



It´s better if you hold it in the middle

[tibu68]

I have used an own made spacer of 45 mm so I can keep the heater valve in place





The sttering reservoir will come from an e34. A special adapter is required



The reservoir in place with new pipes



I had made a 1/4" thread when I repaired the cilinder head. So I can easily connect the vacuum pipe






And finished



Just bleed brakes, steering and enjoy

[ldsbeaker]

No way! Really? (The bomb high pressure line just fits right up?)

A Sixer joins the fold! Thank you so much for sharing!!

[tibu68]

Here you can see the spacer before assembly. With it you can keep the heater valve in its original place. For the e28 should work too.

[dude8383]

Here you can see the spacer before assembly. With it you can keep the heater valve in its original place. For the e28 should work too.

That is really nifty! That E34 power steering reservoir mount bolted up to that bracket by the strut tower or did you have to fab something up there as well?

[Bav Ace]

Here you can see the spacer before assembly. With it you can keep the heater valve in its original place. For the e28 should work too.

Do you have to use a longer yoke to reach the brake pedal bracketing or is there enough threading to accommodate the change in length from the "non-spaced" booster?

[Gooch]

Just finished my conversion and have a very stiff pedal and limited braking ability. It is very reminiscent to when I had the check valve installed backwards when I did my e30 s52 swap. The check valve is oriented properly (arrow towards motor), and functioning correctly.

I thought maybe the diaphragm inside the booster was torn so I swapped a new good used booster in last night. No change.

I just looked on realoem and the master cylinders are the same for 528e vs 535i, I thought that may have been a difference but, no go.

Any ideas? Any help is appreciated, thanks in advance.

[dude8383]

Just finished my conversion and have a very stiff pedal and limited braking ability. It is very reminiscent to when I had the check valve installed backwards when I did my e30 s52 swap. The check valve is oriented properly (arrow towards motor), and functioning correctly.

I thought maybe the diaphragm inside the booster was torn so I swapped a new good used booster in last night. No change.

I just looked on realoem and the master cylinders are the same for 528e vs 535i, I thought that may have been a difference but, no go.

Any ideas? Any help is appreciated, thanks in advance.

Have you adjusted the clevis properly?

[Gooch]

Clevis is adjusted to the same length as the hydroboost unit.

[dude8383]

Clevis is adjusted to the same length as the hydroboost unit.

i dont know if that is necessarily the right length. try messing with it a bit more.

also, did you install a new master cylinder onto the booster? perhaps you missed the gasket that does in between them? lastly, did you fully bleed your brakes...silly question but i gotta ask anyway.

[Gooch]

Good point, I'll give that a shot, thanks.

I reused the master from my car; bent the lines a little to push it out of the way, so I wouldn't have to mess with the bleeding process.

[Bav Ace]

Just finished my conversion and have a very stiff pedal and limited braking ability.

I don't know that I have any great ideas to offer but I am experiencing similar stiff pedal conditions following my swap. I also did a M/C and front brake upgrade at the same time so that may be part of my problem. I don't want to derail your topic so I won't post any more details here but I am curious to see the thoughts other folks have.

Brian