brakes Booster Less?

[73touring]

Hi Folks Ive a leak from one of my newly installed RHD servos. I decided to clamp the vac hose to determine what the effect would be. Stock calipers stock master cylinder. From the brief 10 min drive I took the effort to brake hard was only marginally greater than with the boosters does anyone use a boosterless system on their car and what are their experiences long term?

 

Thanks,

 

Rob.

[Guest_anonymous]

Searching brake booster delete might yield you some experience

[M3M3M3]

many people do and there are a variety of ways to do this.  personally, i tried running without vacuum to the stock booster (LHD tii) on my car and the car was not pleasant to drive on street and really not pleasant on track.  pedal effort was way too high to accurately modulate brake pressure at the threshold point.

 

if you did not notice much difference, either your booster was not working in first place or you were not trying a really hard stop.  or the RHD system is way different feel than LHD.

[LimeySteve]

I run boosterless, to get back the ratio I extended my brake pedal 2" it's just a tad taller than my clutch pedal I have had no problems on street or track. Without extending the pedal it was not good.

[TobyB]

I race without the booster- I like it a lot better.  Modulation's very much improved.

 

On the street, I would think you'd want a smaller master cylinder... or Steve's idea of a longer

pedal's not a bad one!
 

If done safely, it's a matter of taste- and the size of your right (or left, too!) leg

 

t

[M3M3M3]

i should have added that i am not running anything stock in the rest of the brake system.  25mm MC from a 750il and large piston wilwood calipers.  with booster....perfect.  without booster....massive leg pressure required braking at limit from 120+ to 45mph.  i prefer to modulate with my toes, not my thigh.

Edited January 18, 2014 by mlytle

[73touring]

The 750iL MC is has about 25% more surface area so your starting point would be 25% more braking effort before removing the servo not sure about the boost ratio but probably between 1.25 and 1.5 so without the booster something like 1.6 -1.9 times the effort that could be fairly scary in road car allright. Id say it has fantastic feel on the track .

 

Think I should be looking at 1.25 times the effort perhaps 1.5. Ive driven servo-less cars in the past mini's ect with drums all round and found them OK. Ive a volvo 240 brake manifold that im going to use for the project. It has two independent circuits on it with a pressure equalisation valve in the centre. 4 ports per side. The RHD servos are 1 into 2 and 1 into 3. and I believe I can install the manifold with the stock plumbing just a little bending as the orientation is correct and Importantly easily reversible if its too much. 

[M3M3M3]

The 750iL MC is has about 25% more surface area so your starting point would be 25% more braking effort before removing the servo not sure about the boost ratio but probably between 1.25 and 1.5 so without the booster something like 1.6 -1.9 times the effort that could be fairly scary in road car allright. Id say it has fantastic feel on the track .  

 

yes, but I also have larger pistons at the calipers on all four corners of the car which offset the increased force from the MC.   the braking effort is intentionally about the same as the stockish system i had before. (tii MC, volvo calipers, 320 rear drums)

 

as you change the various parts of your brake system there are a variety of brake pressure/balance calculators on the internet that allow you to input MC sizes, disk dia, caliper piston size, etc to calculate front/rear balance and pressure.

[tim385]

Been running boosterless RHD for years, I think that RHD has a different pedal ratio than LHD, ours being a hung pedal, ive never had a problem ,yes, the feel is harder but not that bad . A good brake pad does make a big change .Im running all fronts on one circuit and rears on the other circuit.

Been running boosterless RHD for years, I think that RHD has a different pedal ratio than LHD, ours being a hung pedal, ive never had a problem ,yes, the feel is harder but not that bad . A good brake pad does make a big change .Im running all fronts on one circuit and rears on the other circuit.

[TKMad]

I've been running boosterless for about 3 yearws and I love it!  I used the smalled master cylinder Wilwood had, I think it's 5/8".  The pedal feel is much better (more linear) than the booster and I would say the effort is about the same.

[73touring]

Thanks guys. Ive pluged the Vac for the moment and been trying it for the last couple of days, Sorted my inconsistent Idle problem so some sort of vac leak from one of the servos as well as the fluid leak. So far I have to say Its no no big issue, OK when the pads/disks are cold its requires a fair amount of pressure but when their warmed up on real problem and the warm up in a couple of mins if I keep my foot on the pedal for about 30 seconds driving but really not that nessacary . When I get a chance next week Ill put in the 240 brake manifold in place of the servos. I also have to assume that the braking effort/feel is now at its worst with the servos in place displacing fluid.

 

Ill keep you posted and post a couple of pics on the subjects.

 

Rob.

[73touring]

Just an update on this Ive put the Volvo 240 brake manifold in the 02. This really is only relevant to RHD cars with twin servos.

 

See below.

 

Just completed a servo delete on my touring after fitting successive bad servos in the car. I felt Id try the servo delete to see what It would like in terms of effort and feel.

 

1. Plugged the vac and drove it around like that for an hour or so. Found the feel to be a bit wooden as expected with all that unassisted fluid in the servos cylinders. But the effort was not as much as I feared.

 

2 I acquired a Volvo 240 brake manifold, a twin circuit brake union with 4 inputs on each side. It has a piston in the centre in order to equalise pressure. and an as yet unused pressure switch that the 240 used for the brake lights I believe. 

 

3 I plugged one of the outlets as the servos are set up 1 in to 3 outputs and 1 to two outputs.

 

4 Using this set-up it was possible to keep the stock plumbing and just a little bending to position the pipes I wanted this so that IF required I could go back to stock easily without fabrication of brake-lines ect.

 

I've driven the car around now for a few days with the Volvo manifold in place of the servos and the feel of the brakes is much more linear. There is as you would expect more effort to stop but not an unreasonable amount. If any of you have driven an unassisted mini the effort really is only a bit more than that. Its still easy enough to lock up the brakes and you don't need to go to the Gym to work on your quads to be able to use them.

 

The Braking system is otherwise stock 2002. No brake upgrades have been carried out to the car. I haven't  modified the pedal to increase the leverage.

 

In the event of someone else driving the car you would have to warn them that the brakes need a good shove to stop them, it wouldn't be for someone who has only ever driven a modern car.

 

For me it has been an improvement in feel and response and for the fact that vac and fluid leaks are now gone. THe Pedal feel is very positive and you the point where the wheels lock up is very predictable.

 

It also clears up a lot of space in the inlet side of the engine bay. I just need to clean down my chassis leg of all the years of brake fluid leaks and repaint it.

 

I Hope this has been of help to someone.

 

Rob.

[M3M3M3]

good info.  thanks for following up with the details!