Upgrading RRC brakes

**walker** · 24th September 2009, 09:30 PM

Hi all, just wondering if it is necessary to upgrade the master cylinder if you convert the front brakes from solid to vented brakes.

During the "dancing hippo" project on my 87 rangie I installed vented and slotted discs along with brand new calipers from a later model rangie.

My problem is that I don't think the brakes work as good as they should. All calipers seem to be working and peddle is not spongey at all but it just does not pull up well. If I jump on the peddle as hard as I can, the wheels don't even lock up.

It also has a brand new master cylinder. I was wondering if the pistons on the later calipers were larger and the standard master cylinder is not providing enough pressure????

**Slunnie** · 24th September 2009, 10:16 PM

Pads make a biiiig difference.

**walker** · 24th September 2009, 10:26 PM

I did ask for soft pads, but I really don't know how soft/hard they are. They are mintex pads.

**Lotz-A-Landies** · 24th September 2009, 10:40 PM

Originally Posted by Slunnie

Pads make a biiiig difference.

So does air in the system. Are you sure you bled the new callipers correctly and completely?

I did exactly the same conversion on my '85 RRc but didn't change the master cylinder and found a noticeable difference, although still not as firm as my '92 RRc. The difference is a bit disconcerting when I swap between Vague the '85 which I prefer to drive and Blue the '92 back-up car which has ABS.

Diana

**walker** · 24th September 2009, 11:14 PM

I am going to get another bottle of brake fluid and bleed it all again, but pretty sure their is no air in the lines. The pedal is nice and firm........just a lack of stopping power. It probably doesnt help with 35" tyres on but I am sure my old 2 door stopped better.

Maybe its just that I have not drive an old Rangie for 2 years and forgot how bad the brakes are.

Rangier Rover · 25th September 2009, 09:03 AM

Are you using a Rangie or disco master cylinder. When my Rangie goes onto 35s I'm changing to a Disco master cylinder and larger Defender front calipers with vented disk. Then may be remove the proportioning valve or fit a variable one.

**Scouse** · 25th September 2009, 09:18 AM

When I had both my '87 & '88 on the road, the difference in the brakes was very noticeable. The '88 pulled up much better than the '87.

The '88 has a different booster/MC than the '87 so I put the difference down to that (everything else was the same - brake pads/tyres).

**steveG** · 25th September 2009, 09:19 AM

I know nothing about RRC, but have had braking performance problems from lack of vacuum or leaking booster diaphragms.

Steve

**walker** · 25th September 2009, 10:35 AM

thank all. It is quite possible there is a problem with the booster diaphram, just not sure how to check it.

I had every intention of going to a Disco master cylinder and booster but it was not as easy as just a straight replacement. Will have to investiget further.

**steveG** · 25th September 2009, 10:26 PM

Originally Posted by walker

thank all. It is quite possible there is a problem with the booster diaphram, just not sure how to check it.

I don't remember the exact details, but its along the lines of:
1. Run the engine for a couple of minutes
2. Turn off
3. Wait for about 20 seconds (not sure about the waiting time)
4. Apply and release the brakes - you should get at least 3 decent applications before the pedal goes hard due to no vacuum.

I know I got the info somewhere on this forum so a search should find it.

Steve

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