Very "iffy" Brakes on a Rover 620ti.

[MGJohn]

Not my 620ti, they're all just fine, but spent a couple of hours on my son's high mileage 620ti yesterday afternoon. Following his lap with four adults on board at the Nurburgring, his brakes have been a bit "iffy". Nowhere near how the fine brakes on a 620ti should be. Low pedal and maybe a little pedal creep. He's been using one of his other cars whilst pondering how to fix the 620ti. Making things more difficult for him working sixty miles away Mon-Fri.

Anyway, he suspected his Brake Master Cylinder was the problem and he carefully removed one from a scrapyard 600 after checking that it worked well before deciding to get it.

So fixed it to his car and despite careful bleeding, the brakes were still far from ideal. So being home this weekend, we spent some of this sunny afternoon investigating the brake problem.

I decided to try something which had worked for me in the distant past with a similar problem on an MG Montego Turbo. I relaxed the two fluid line unions one at a time, in turn on the master cylinder and bled those with my son operating the brake pedal with me nipping up the union nut when I was satisfied no air emerged, just pure fluid.

My son Martin felt things were a little better, but, when I tried the brake pedal, I could 'feel' a little pedal creep and still far too low. At least a firm higher pedal was achieved after three-four pumps but nowhere, near good enough.

Earlier I had fitted four new Brake Pads to the front Calipers after cleaning the exposed parts of the Caliper Pistons with Brake Fluid. Only when clean did I retract the Pistons to retain their smooth operation. The old brake pads were well worn. At least we now knew the front pads were up to the job.

I then carefully bled the front nearside Caliper, then the front offside, then the offside rear ~some bubbles and clouded fluid from this caliper ~ and finally bled the nearside rear. My son showed obvious delight he now had a firm and high pedal. Still a bit wary, Dad's tend to worry .. ... I took the car for a drive and progressively used the brakes to bed in the pads. With each of about ten applications, the progressive improvement was impressive.

Both firm applications at speed and normal pressure at lower speeds showed further improvement.The car brakes well now and will return to daily use soon.

Such a relief when a puzzling problem is solved after investing a couple of hours and work into a job.

I shall rest easy when my son drives that car now.

This is the simple basic kit I used and have always used when bleeding the hydraulics on any of my cars for decades. It works.





One worrying thing. He told me the ABS light illuminated and flickered at speeds above 100 mph when in Germany. Never heard of that before. I have braked a 620ti hard from 140 mph indicated and the ABS really kicked in more so than on any other car I've experienced as the car passed over a less than even smooth service. The car pulled up in a straight line right down to stopped. ABS works well ... well it did on that 620ti

I'm usually easy on brakes and a year will pass, maybe more without any of the cars I drive ever deploying their ABS. Even so, I like to test the ABS operation. When my field is a still a little wet from recent rain, I drive over light rough grass at 30-40mph and hit the brakes. That deploys the ABS and you can feel the pedal pulsing as the ABS valves do their work. It's a good DIY test and confirmation that the car pulls up straight even though the wheels are more than doing their stuff over the slippery terrain. Works just as well when steering to one side as well.

That Lap of the Nurburgring is on YouTube too. They had fun at speed although with that heavy load on board, they were overtaken far more than they overtook ... Some of the passing cars were very fast exotics making lovely sounds.

Now well over 210,000 miles, his 620ti still goes well. Good eh ... Made of good stuff those 620ti :~

https://www.youtube.com/watch?v=lEQ07qg7zcs

Edited by MGJohn on Monday 30th March 01:11