Brake booster

[dulcimerbob]

How can I test my brake booster to see if it's working ? I read one poster that said she did away with the booster and really noticed little difference in brake performance. Need help.

[mdrburchette]

Disconnect the vacuum hose and plug it. That should eliminate the booster.

[kmead]

There is a huge difference in effort between with and without.

You can remove the vacuum hose from the manifold (be sure to plug the pipe on the manifold) to test the booster.

You may have a failed vacuum hose already which could be affecting the function of the booster and leaning out your mixture.

There is also a one way valve on the vac hose to hold vacuum in the booster which could be on the wrong way as well as it being defective.

The braking system of the 124 is quite manageable without a booster (and is frankly touchy easy with it) but does require a healthy right foot to bring the car to a stop.

[BEEK]

drive a x1/9 it has the same basic brake system as the spider, master cylinder bore and caliper bore sizes. they stop just fine with no additional pedal effort. its a false feeling to disconect the booster. and think thats what you will get. i have driven fiat 124 coupes with no booster, modified the pedal and booster plate and eliminated the booster for side draft carbs. car stopped fine

[dulcimerbob]

What type of mods are needed for the pedal and booster plate ?

[htchevyii]

I did the conversion on my '72, although I haven't got to drive it much. Denise reports good results with her's, more info here:
http://www.fiatspider.com/f08/viewtopic ... ual+brakes

[BEEK]

pushrod length and a mounting plate for the master cyl

What type of mods are needed for the pedal and booster plate ?

[mdrburchette]

I didn't have to do anything for the pushrod length for the master cylinder. I've done the conversion on my 71 and now on my 78 lemons racer and all I did was make a plate to make the hole smaller for the m/c and connect the rod from the m/c to the brake pedal. Running with the booster still on the car but with the vacuum hose closed off will result in a slightly harder pedal than with the booster completely removed.