Leading shoe, springs beware.

[Keith Clements]

Working on Peter Pfister's early Jav yesterday I had to step back and have a good think. The problem was I could not get the front brake to adjust and one shoe was rubbing. I resorted to reading the manual which said the upper spring should be attached to the trailing shoe. Now I know Peter is not Italian, so normally uses his Jav in the forward direction. On that assumption the nearside (on a RHD) or left (sitting in driver's seat) front wheel normally turns anti-clockwise, thus the trailing shoe is on the right as the expander is at the top. Now I had to double check on my notes for the full hydraulic system and consult Google to double check on what a trailing shoe was. Google was not being clear as it was clogged up by some poor advice from some American forums!

Well having had the drum on and off several times I have now decided the spring is on the wrong shoe.

A leading shoe is so called because the expander pushes the shoe onto the rotating surface of the drum and this surface of the brake material next to the expander leads in front of the material at the static end. The grab caused by the friction at this surface tends to increase the pressure on the drum thus acting as a servo assist. The opposite happens at the trailing shoe in that direction as the drum tries to throw the shoe off the drum surface. But when operating in Italian mode the trailing shoe takes on the leading shoe's role.

The amazing thing is we drove it all the way from Switzerland like that. Now I will look at the other side.

On full hydraulic the front brakes are both leading shoe as there are two expanders

[Keith Clements]

I suspect the June 1950 maintenance manual page 55 para 120 is incorrect. Why? Well the 1948 parts manual page 23 shows the LH backing plate with the snail cam to the left and spring anchor point on the right. The leading shoe is to the left on the LH side as the wheel rotates anti clockwise (unless you were viewing from under the car ) with respect to the hub when in forward motion.

Anyway that is how it is on Peter's car and the brakes work but do not adjust; but there is still the possibility that both his car and the parts manual are wrong (or I am being stupid about what is the trailing shoe). The alternative is to swap backing plates to agree with the maintenance manual and disagree with the parts manual.

[Keith Clements]

I knew I should have consulted the Technical Manual. Part XXVI Page 16 Girling Service Bulletin. Sure enough it says the spring goes to the leading shoe. I knew I should never have RTFMed.

So do not worry Peter, the brakes are OK. Just need to adjust them now.

Whilst sifting through the notes which make interesting reading for Jowett nerds I came across the Varied Cures article by JD Taylor Pg 31 and 32 if you number the pages in section XXVI. Hell, I never realised the camber changed and to cure it a tie bolt was put along between the chassis rails to pull it in!

[p.p.]

IM NOT WORRY JUST WONDERING

YOU WILL DOIT

PETER