Easy DIY Fix On Rear Brakes - By Bennie Hurter (aka Benhur)

Many guys struggle with the brakes on their Hiluxes especially the SFA models. Many times the problem is to do with the rear brakes.

One of the major problems is that the mechanism in the rear drums is dirty or rusted due to a lot of mud and water driving. This article does not cover the servicing of these drums but goes beyond to another problem that guys experience which actually has a fairly simple fix, if only people knew about it.

Guys tend to service and adjust the rear brakes in an attempt to get the brakes to work better but many times they forget an important piece of the puzzle: the LSP & BV :? :wink: :wink:

This article covers the working and adjustment of the Load Sensing Proportioning and Bypass Valve. The aim of this valve is to adjust the pressure which is applied to the rear brakes in relation to the amount of weight that is loaded onto the vehicle.

If you look at the set-up of this valve it reminds you of a ball float of a toilet’s reservoir and it works similarly.

As the weight on the vehicle increases, the suspension is pushed in and the body/chassis move closer to the rear axle. This movement is sensed by the LSP&BV also known as the Load Sensing Valve and it increases the pressure which is applied to the rear brakes accordingly.

On a new vehicle, this valve works fairly well, but on older vehicles with sagging suspension or on vehicles with suspension lifts and modifications, the suspension geometry falls outside the normal working parameters of this valve. Then it needs to be adjusted or modified to work.

The Service Manual shows a fairly complicated way of setting this valve using fancy pressure gauges that must be attached to the front and rear brakes and pressures must be measured and this valve be adjusted to get the pressure ratio to within specifications.

Click here to download the pdf file

However, most of us do not have the time or equipment to do it that way so we must do it the “Trial and Error” or “Hit and Miss” way by adjusting shackle no 2 and then driving the vehicle to test the effect.

After lifting my rear suspension by replacing rear leaf blades and lengthening the shackles, I realised that my rear brakes were not working anymore.

I tried adjusting this valve but could not get it to work again so I decided to lengthen the Shackle no 2 with about the same amount of suspension lift I gained. In the photograph below I extended the shckle by welding piece of round bar into it.

Another way to extend the shackle is by using a "long nut" .
See the next two photographs:

The picture below shows Frik and his son's modification:

Afterwards I saw that you could also move the valve itself to help with the adjustment,
but I doubt that it would have been enough.

After this lengthening exercise, I could then adjust the length of Shackle no 2 until my rear
wheels were braking but not locking up too quickly on Gravel or wet Tarmac.