ae101 rear brake balance

krock · Post by **krock** » Mon Nov 29, 2010 9:43 pm

hi, my car (ae101 fxgt) has a large imbalance between rear brakes, mechanic has suggested that it is probably the brake proportioning valve as these fail fairly regularly on toyotas, or maybe it was corollas in particular.

From what i gathered the disks, calipers and pads were ok as he didn't find any problems with them other than a bolt which was missing on a caliper and he replaced for me.

can anyone back this up? a) that this could be likely cause of imbalance, and/or b) that this is a common problem...

Cheers for any help

Lloyd · Post by **Lloyd** » Mon Nov 29, 2010 9:52 pm

Yes and yes. You don't trust your mechanic?

Bling · Post by **Bling** » Mon Nov 29, 2010 10:10 pm

Yes and Yes.

strx7 · Post by **strx7** » Tue Nov 30, 2010 5:51 am

there was a thread about these 7-10 days ago

krock · Post by **krock** » Tue Nov 30, 2010 4:47 pm

thanks for the help

rollaholic · Post by **rollaholic** » Tue Nov 30, 2010 5:49 pm

send valve to yems for rebuild, way cheaper!

krock · Post by **krock** » Tue Nov 30, 2010 6:24 pm

ok, i'll ask him . cheers

allencr · Post by **allencr** » Tue Nov 30, 2010 7:39 pm

Is there actually valve between the LR and RR brakes or just a T?
If it doesn't have a problem between the F & R where the valve is plumbed in, then it isn't a valve problem!

***
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[quote=Matt Dunn]Almost all FWD cars are split diagonal braking systems, [/quote]

Thanks, news to me, except for what Volvo's been doing for 40 years.[/b]

matt dunn · Post by **matt dunn** » Tue Nov 30, 2010 9:32 pm

allencr wrote:Is there actually valve between the LR and RR brakes or just a T?
If it doesn't have a problem between the F & R where the valve is plumbed in, then it isn't a valve problem!

Almost all FWD cars are split diagonal braking systems,
so the LR and RR are not connected at all, there is not a "T" as you say,

and from my understanding they kinda have two valves, one for each rear wheel, so one can jam and you get too much brakes on one rear wheel, although both thye valves are built into one unit.

Bling · Post by **Bling** » Tue Nov 30, 2010 9:48 pm

Do cars with ABS use the same valves?

eg ae111 abs
ae111 non abs?

matt dunn · Post by **matt dunn** » Tue Nov 30, 2010 9:56 pm

BZG|Bling wrote:Do cars with ABS use the same valves?

eg ae111 abs
ae111 non abs?

I would presume so as you still need the same bias with abs,
otherwise the abs would kick in to stop locking the rears everytime you braked.

TRD Man · Post by **TRD Man** » Tue Nov 30, 2010 10:24 pm

Old Toyota brake hoses (about the age of AE101) have been known to collapse internally causing a blockage which will effect the balance.
It is far easier, and less costly, to check this before the proportioning valve.

rollaholic · Post by **rollaholic** » Wed Dec 01, 2010 6:44 am

there are also two types of P valves, one with an alloy hosing and i believe 5 inlet/outlets and one with a cast housing and only 4

or something like that

krock · Post by **krock** » Wed Dec 01, 2010 5:37 pm

TRD Man wrote:Old Toyota brake hoses (about the age of AE101) have been known to collapse internally causing a blockage which will effect the balance.
It is far easier, and less costly, to check this before the proportioning valve.

apparently i have a "cracked" rear brake hose, i havent checked it out yet, and im not sure if it could be cracked and not be leaking, but maybe that could be connected with my imbalance and not the prop valve...

rollaholic · Post by **rollaholic** » Wed Dec 01, 2010 6:55 pm

the outer sheath can be cracked or perished from age / heat etc with the inner section retaining its integrity, for now at least.

krock · Post by **krock** » Wed Dec 01, 2010 7:23 pm

yeah ok. so could be either/or then. have to try one first then.