Is Having To Pump The Brakes Normal?

[Guest red-col]

Hi All,

 

Nearly ready for the car to go for an IVA, got a lot of trimming up the sharp edges and one or two other jobs to finish off but my main query at the minute is the brakes?

 

The master cylinder is from the original donor sierra (all seals have been replaced) as well as 4 brake calipers (again all seals replaced) for discs.

All pipe work and fixings are brand new and we are unable to see or feel any leaks anywhere on the system.

We have not fitted the servo unit to the kit.

We have made sure there is no air in the system by bleeding all the brakes many times.

 

The problem is when you first press the brake pedal it goes to the floor however if you pump the pedal 2-3 times then the resistance gets more difficult and you seem to get good brakes.

 

Is this OK for IVA reasons?

 

If not will fitting a servo of some kind resolve this 'issue' and satisfy Mr IVA man?

 

Any help greatly appreciated.

[Grim]

Errrrm, does not sound right to me!

 

Clamp your brake hoses to find the problem caliper (or master cyl).

Have you got the front calipers on the correct side (nipples up!)? Are the caliper seals are underlubricated and pulling the pistons in excessively (pop pistons out and lubricate with fluid)? Or just good old fashioned air!

 

Having a servo wont change the fact you're needing to pump the brakes.

[Guest mower man]

If you have removed the servo you should have a realy firm pedal I can guarantee it won't pass IVA or MOT and should not be driven untill you don't have to pump the pressure up you must have a problem with air or a leak in the system ,check all connections etc , if any thing older cars in good condition usualy have a wooden feel ,sorry but you have a problem but for your own safety sort it, it's the worst possiblething a car that won't stop !! mower man

[Guest red-col]

OK Cool another thing to add to the list of things to do when not at work

 

good job ive not booked the IVA just yet

[Longboarder]

The fact that you can get a firm pedal by pumping and the brakes do then work suggests the hardware is OK. The most likely problem is air still in the system and as Grim pointed out the most likely cause of that in a new build is calipers fitted to the wrong side of the car. The front left caliper will happily bolt on the right side and vice versa and look absolutely correct till you notice the bleed nipple is at the bottom of the caliper. It has to be at the top. Swap them side to side, bleed and all is well.

 

Nigel

[Guest red-col]

The fact that you can get a firm pedal by pumping and the brakes do then work suggests the hardware is OK. The most likely problem is air still in the system and as Grim pointed out the most likely cause of that in a new build is calipers fitted to the wrong side of the car. The front left caliper will happily bolt on the right side and vice versa and look absolutely correct till you notice the bleed nipple is at the bottom of the caliper. It has to be at the top. Swap them side to side, bleed and all is well.

 

Nigel

 

I now have a picture of my car in my head with the calipers on the wrong way round so ive got a feeling this could be the solution.

 

However until i check it later i dont know for definate.

 

Cheers for this

[Guest red-col]

OK so had confirmation that the calipers are on the right way with the bleed nipple on top of the caliper.

 

looks like im gonna have to re-check every connection etc and go from there.

[steve in stockport]

I recall something about the rear calipers being mounted in a different orientation on the Zero to on a sierra, and in some cases needed the calipers removing and holding upright to get the air out.

But then again I may have imagined that!

[Peter Bell]

Have you got the Sierra pressure compensator fitted? they can be hard to bleed and not necessary!

[Guest red-col]

Peter bell: not knowingly. All we have fitted is the master cylinder pipes 4 way union at the rear and the necessary male and female unions for the braided hoses.

[Guest mower man]

Have you got the Sierra pressure compensator fitted? they can be hard to bleed and not necessary!

If you have the above lump of s---e fitted take it off and throw it in the skip ,as Peter says they are not necessary mower man [whoops I may have poked astick in a hornets nest]

[harvs]

Clamp your brake hoses to find the problem caliper (or master cyl).

 

As Andy says above, try isolating the problem. I used this technique which traced it to one calliper. Even though I'd pumped through loads of fluid there was still air trapped in this one corner. Lots more fluid & taking it off and turning it in many directions got there in the end....

 

Good luck

[Snapperpaul]

Here's a trick I was taught, first off put 3 bleed nipples in the master cylinder, bleed each one in turn until pedal is firm, if the pedal is not firm it's the master cylinder, if one of the bores is worn or scored, new seals won't cure it,

If you have a firm pedal connect one front brake (the one closest) and bleed til firm, connect next front break bleed until firm, then the rears.

That should work or at least isolate the problem area.

Edited April 4, 2011 by Snapperpaul

[speedtripledan]

If you have the above lump of s---e fitted take it off and throw it in the skip ,as Peter says they are not necessary mower man [whoops I may have poked astick in a hornets nest]

Steady Mower man

[Guest mower man]

Steady Mower man

It's my age you know I get a kick out of being contraversial [read as blooy awkward] mick [mower man]