Title: Power Booster not very powerful Post by: simins on May 19, 2008, 11:55:36 PM Hi guys I have a braking delema just over twelve months ago I purchased another project a modified FE Special Sedan.
Fitted with a 179 red motor ,syncro 3 speed ,floor shift, LC/LJ Torana rear end and drum brakes,HR front end with LH/LX disc rotors and calipers , VH44 remote booster ,HQ master cylinder mounted on a hadfield adaptor. the car was driven onto a trailer then off again driven once around the block then into the garage for major rust removal,A pillars front floor pans, inner and outer front sections of sills. I also installed a replica hadfield chassis kit. The motor recieved further mods with the addition of tripple 1-3/4 SU carbs, yella terra head with large valves and an XU-1 style of camshaft. The next time the car was driven was tuesday before the nationals and of course to the nationals. The probiem is the car has a very hard wooden feeling brake pedal, I dont recall the feel of the pedal on the day of the quick drive around the block. So my questions are is this a faulty brake booster? a lack of vacumme due to camshaft timing and duration? Do i need a vacumme tank? How do i test a booster unit? Or should i install afirewall mounted booster / master cylinder unit and rear brake proportioning valve? Install an alternator with a vacumme pump? maybe Ken or someone else may have some ideas. thanks in advance Simon Addison Title: Re: Power Booster not very powerful Post by: mcl1959 on May 20, 2008, 05:05:58 PM For a start the VH44 is not really suitable for discs - you should get a VH40. Next it is quite possible for the booster to die if left inactive for a while. Try the brakes with the booster vac hose attached / unattached to see the difference - you should notice a difference. Large cam will drop vaccuum, but first stop will be OK then subsequent stops no good
Ken Title: Re: Power Booster not very powerful Post by: simins on May 20, 2008, 06:30:15 PM Thanks Ken that should have read VH 40 for the booster which has been in the car since the 70'S
Simon Addison Title: Re: Power Booster not very powerful Post by: Trevor_B on May 21, 2008, 11:17:05 AM Hi Simon,
I run a Vacuum tank in Chris's green FC ute due to cam, Engineer prefered one was fitted. It has a Gemini Booster & VN Commo master Cylinder. Hard pedal feel was reduced a little with new reaction disc in booster and "softer" pads although went hard again on idle on subsquent applications at low revs hence the Vacuum tank. PBR still have small tanks available although not listed - about $150 I think. If you want to try one out perhaps you can come down one day and we take the one out of Chris's ute to test your car (don't tell her about it ;) ) Trevor_B Title: Re: Power Booster not very powerful Post by: ownfc59 on May 21, 2008, 11:40:25 AM Hi all,
Just chiming in on this thread with a related question. I have a stock standard FC with the usual drums all around. Would fitting a brake booster be of any tangible benefit? At the moment she pulls up pretty well but the pedal is extremely firm underfoot & takes a bit of downward pressure to engage brake fully. If it would be of benefit, next questions are - What type is best to get & what is involved with installation? Would it be possible to fit myself with my limited (but slowly increasing) mechanical knowledge? Thanks, Pete Title: Re: Power Booster not very powerful Post by: mcl1959 on May 21, 2008, 06:51:43 PM Ensure that brake cylinders are all working freely as stock brakes should not be overly hard to operate. Having said that - there was a factory booster available as an extra (the advertising showed a delicate old grandma behind the wheel). Nowadays a VH44 booster is used for 4 wheel drums and will reduce pedal effort somewhat. Brake booster is installed inline between the master cylinder and the T junction. Vacuum is sourced from the manifold. Easy to fit with experience but unless you are confident with bleeding brakes I would leave it to an expert or get someone round to help once you have fitted all the components up.
Ken Title: Re: Power Booster not very powerful Post by: simins on June 09, 2008, 08:40:26 PM Thanks for all the help turns out car only had a VH 44 bosster. Has been replaced with rebuilt VH40 much better car now stops with a lot less pedal pressure and more feel to the pedal
Regards Simon Addison |