Pulsing Brake

Rhod · Post by **Rhod** » Wed Jan 23, 2008 9:27 am

I wonder if anyone can throw any light on this?

The Bongo is a '96 one, without ABS.
Due to my New Years resolution of cycle commuting the bongo tends to sit idle most of the week, in Park, without the handbrake on (too many experiences with shoes sticking on in the damp climate on previous vehicles left parked up for extended periods). Heading away for the weekend last Friday I got a heavy pulsing through the brake pedal on braking - "bugger" I thought "wonder which of the discs are warped". I've had warped discs before on an Astra & it felt exactly the same. About 40 miles up the road however, coming down to a junction the pulsing had disappeared & hasn't returned yet.

I've had something similar on the bike before, but with far less pulsing effect - that was due to corrosion on the cast iron disc after a winter outside in the sea air.

I'm guessing that the effect on the bongo is due to a build up of corrosion on the disc(s), since I've never heard of warped discs un-warping themselves, but does anyone have any thoughts?

Rhod

Harry · Post by **Harry** » Wed Jan 23, 2008 11:15 am

I've had a similar experience and my garage told me it was corrosion and advised parking without the handbrake on (gear lever in park). Seems to have solved the problem.

H

Hooligan · Post by **Hooligan** » Wed Jan 23, 2008 11:17 am

To be honest, I never use the handbrake when parked. (2.5TD Auto)
Is that a bad thing???

Post by **Ian** » Wed Jan 23, 2008 11:23 am

It can be. See here http://www.igmaynard.co.uk/bongo/tales/haydn.htm

Hooligan · Post by **Hooligan** » Wed Jan 23, 2008 11:28 am

I'm not sure I see what you mean Ian. In PARK the gearbox is locked and won't shift unless foot is on brake pedal anyways. So it needs a deliberate action to move the van.

Post by **Ian** » Wed Jan 23, 2008 11:30 am

The point I was making is that Haydn suffered because he parked without the handbrake on AND left it in gear

Ralph · Post by **Ralph** » Wed Jan 23, 2008 11:39 am

Rust on't discs you get the pulse as part of it as had
the pads in contact over night, after you brake a few
time they wipe themselves clean, Had a van that did
it many years back I used to press lightly on the brakes
for the first 100 yards or so in the morning, don't know
why some discs seem prone to it others not, ours doesnt
do it and is parked 200 yards from the sea but driven most
days.

Hooligan · Post by **Hooligan** » Wed Jan 23, 2008 11:43 am

Oops!

Mr Halibut · Post by **Mr Halibut** » Wed Jan 23, 2008 12:49 pm

| have read various articles suggesting parking (on an incline) and only using park to keep the car still can put undue stress on the park pin mechanism. Also putting the car into park when not absolutely stationary can cause damage.

bigdaddycain · Post by **bigdaddycain** » Wed Jan 23, 2008 2:41 pm

I suspect the reason that some vehicles suffer from this phenomena,whereas others dont, is simply down to the amount of chafing of the pad on the disc,up till the point where the brake pedal is applied.

If the disc have been gently cleaned by the pad slightly touching the disc,the pulsing effect will not be noticeable when the brake is applied.

coco bongo · Post by **coco bongo** » Wed Jan 23, 2008 3:41 pm

Handbrakes are there for a reason SAFETY. Always use it.

We all know that it will hold very securely in park, But there will come a day you will do something completely without thinking about it. And then your pride and joy turns into Herbie.

Ideally you only want to have handbrake off, and in park when you are not going to be using the Bongo for a prolonged time. (saving your rear brakes sticking).

Dont be one of the unlucky ones!.

Colin Lambert · Post by **Colin Lambert** » Wed Jan 23, 2008 4:53 pm

You should NEVER leave an automatic 'hanging' on the gearbox on a hill with the gear lever in 'park' you will cause HUGE strain on the gearbox as it fights to hold nearly 2 tons of Bongo in check. ALSO ALWAYS come to a COMPLETE stop before going int P. If you don't you WILL break something in the g/box!
I ALWAYS (even on the level) pull the handbrake on first and THEN put the g/lever into P . This way it ensures nop strain on the gearbox.
Leaving the hand brake on will not cause any pulsing as the handbrake on a Bongo is by DRUM & shoes nothing to do with the discs and pads.

dandywarhol · Post by **dandywarhol** » Wed Jan 23, 2008 5:12 pm

Agree with all you're saying there Colin but there's every chance that the shoes will corrode to the drum if left on over a long period.

Rhod · Post by **Rhod** » Wed Jan 23, 2008 6:30 pm

I think I managed to get 2 topics going together there......

I wasn't trying to link the handbrake issue to the original brake pulsing query.

Leaving the bongo idle for week at a time, I suspect from previous experience & local climatic conditions that I will get problems with the shoes corroding to the drums, if the handbrake is left on (I think the owners handbook makes mention of this & advises leaving it off in some circumstances. I'm only talking about extended park-ups, not daily use, and only in a controlled area - i.e. my drive. I fully take on board the issue of damage to the gearbox by leaving in in Park only, hence the idea of a permanent chock for the wheels, in my drive.

Colin Lambert · Post by **Colin Lambert** » Wed Jan 23, 2008 11:43 pm

You're ok leaving it in park with no handbrake on your drive as long as it is dead level.
I would never leave an automatic in PARK only on the road in case someone ran it up the back , that would break the gearbox and push it into what ever was in front of it.